Referencing and RefWorks

APA Referencing

APA format is produced and standardised worldwide by the American Psychological Association in their Publication Manual of the American Psychological Association, often simply referred to as the "APA Manual" (copies in RGU library). The APA Manual is a style guide that covers all elements of producing a manuscript, including citing and referencing, and is used in psychology and a number of other disciplines. The current version is the 7th edition (2020), which included some changes over the previous 6th edition (2010) and older 5th edition (2001), but you are unlikely to be penalised if you use the older editions and they are still covered in some textbooks. This guide covers the 7th edition.

Why Reference?

WHY DO I HAVE TO REFERENCE?
To support your arguments by referring your reader to academic sources which confirm what you are saying
To give credit to the other authors whose work you have quoted, or to whose work you have referred
To avoid a charge of plagiarism
To allow the reader of your work to find the books, journal articles, web pages etc. which you have read
To demonstrate that you understand the conventions of academic writing
WHEN DO I REFERENCE?
Every time you quote directly from someone else's work
Every time you refer indirectly to the work of someone else, e.g. if you:
  • paraphrase what they have said
  • summarise their arguments or ideas
  • quote case studies, statistical data, known phrases, definitions etc.
  • use information which you have obtained from their work
When you wish to provide sources of further information, clarification of points you have made in your text, or additional evidence to support your arguments

What is...

Plagiarism

You may have heard "plagiarism" (and the need to avoid it) mentioned by your lecturers but be unclear what it is.

It is not only acceptable, but expected, that you will refer to the work of others in your academic writing. This gives authority to the points you are making and demonstrates the breadth of your reading. However, you MUST provide appropriate citations and references when you do so.

Plagiarism occurs when you use other people's work without acknowledging that you have done so by citing your sources and providing references for them.

This guide explains the APA style of referencing. If you correctly follow the APA style explained here, you will avoid any risk of plagiarism.

If in doubt, reference!

For more information, see RGU Study Skills' guide to Academic Honesty (via Moodle).

Paraphrasing

This is when you take someone else's ideas, theories, opinions, etc. and express them in your own words. This should be the main way you cover the material, using your own words to describe it rather than direct quotes.

Paraphrasing is great because you can show your understanding of the concept. However, putting information into your own words doesn't mean it is your own original idea. So, you must reference the originator of the idea. If you don't, it will constitute plagiarism, which we're sure you'll want to avoid!

Only information which is considered general knowledge, or common knowledge within your field of study, does not have to be referenced.

More information on plagiarism can be found on the RGU Study Skills unit’s section on Moodle, or in the following books available from the RGU Library, each of which has a relevant chapter:

Parson, V. (2018). Study and Communication Skills for psychology (any edition). Oxford University Press.

Smyth, T. R. (2004). The Principles of Writing in Psychology. Palgrave Macmillan.

Directly Quoting

This is when you copy the exact words from a book, journal article, website, etc. It's ok to include quotations here and there in your assignments, but try not to overdo it, as too many quotations might get frowned upon. It is your work as well! A few things to keep in mind:

  • short quotations can be contained in your paragraph and should always be “enclosed within quotation marks”
  • Quotations of 40 words or longer should be indented as a separate paragraph (i.e. a “block quote”) and do not require quotation marks.
  • unless you are quoting from material which does not have page numbers, you will always need a page number (or time index for audiovisual sources) as part of your in-text citation when quoting. If material does not have a page number or time index, use another way to help the reader find the quote (e.g. paragraph number or name of section).

All quotations need to be referenced properly. If they are not, this constitutes plagiarism.

Stages of Referencing

There are always two stages in APA referencing - the citation in the text, and the reference list at the end of your document.

If you are new to APA format, you may find it useful to visit the APA's style homepage, and their quick reference guide. You can also check their blog page (which often has examples of obscure types of sources).

The citation is inserted into your text where you have quoted from, or referred to, someone else's work. APA uses an “author-year” method when citing in text.

Features

The citation is placed in brackets in your text and consists of:

  • the surname(s) of the author(s) of the source as they appear in the reference list at the end of your work, followed by a comma
  • the year of publication of the item,
  • and a page number(s) but IF (AND ONLY IF) you quote directly from someone else's work in quotation marks. Otherwise, no page numbers.

Citations must be within the sentence (i.e. before any full stop). A common mistake in student work is to put the citation outside the sentence, as follows:

WRONG: The core conditions are congruence, empathy and unconditional positive regard. (Rogers, 1956)

CORRECT: The core conditions are congruence, empathy and unconditional positive regard (Rogers, 1956).

Methods

You choose from two methods depending on how it fits the text. Most writing uses both of these methods, as fits the sentence.

  • Method 1) Authors’ surname(s) are listed in the sentence, followed by the year in brackets right after the name(s), for example: Rogers (1956) proposed that three core conditions are necessary and sufficient for therapeutic personality change.
  • Method 2) At the end of the phrase or sentence, all in brackets are the authors’ surname(s), followed by a comma, then the year of publication, for example: Three core conditions may be necessary and sufficient for therapeutic personality change (Rogers, 1956).

If citations is 1 or 2 names: Give all names every time you cite them, as in: Rogers (1956) or (Carver & Scheier, 1998).

If citation is 3 or more names: Shorten to the first surname et al., as in the following: Doe et al. (1993) found that…

An exception is that if, by shortening to first author et al., two different sources are going to be cited the same (causing confusion). In that case they need to be differentiated. This is done by adding extra names sufficient to differentiate the two references. For example, if you would end up with two different sources both cited as Bloggs et al. (2018), then you would make one Bloggs, Doe, et al. (2018) and the other Bloggs, Smith et al. (2018). Add only enough extra names to make them differentiated. Don’t make one (2018a) and the other (2018b) unless all the authors’ names are identical.

If your citation is all in brackets, such as (Carver & Scheier, 1998), then separate them with an ampersand (&). If only the year is in brackets and the names are just in the sentence, separate them with the word “and”, as in: Carver and Scheier (1998) proposed that…

Examples

When you paraphrase: It has been proposed that... (Rogers, 1956)
When you paraphrase and want to use the author(s) name(s) in the sentence:
  • Rogers (1956) claims that ...
  • Carver and Scheier (1998) argue that ...
  • Levinson et al. (1978) suggest ...
When you directly quote: One definition of psychology is the "scientific study of human mental processes, motivations, and behaviour" (Heffernan, 2014, p. 1).
When you directly quote and use the author(s) name(s) in the sentence: Heffernan (2015, p. 1) defines psychology as the "scientific study of human mental processes, motivation, and behaviour". 

Features

  • located at the end of the main body of your work and gives the full details of works to which you have referred, in a specific format.
  • arranged alphabetically by author.

Please note: the reference list contains only works you have referred to and cited in the text, and no others. It is different to a bibliography (i.e. a list of all sources consulted even if not referred to in the text). Bibliographies are usually not used in APA format, but a reference list must always be present.

For the most up-to-date detail, including additional source types not covered in this guide, you can consult the current edition of the APA Manual itself (a publisher is not included in the APA-format reference below, though it is for most books, because in this case the publisher is the same as the author and is omitted to avoid repetition).

American Psychological Association. (2020). Publication Manual of the American Psychological Association (7th ed.).

Reference List: Basic Rules

How do I enter authors, corporate authors, different editions and different sorts of places of publication in my reference list?

REMEMBER:

APA format has different rules for how many authors to include for the in-text citations (see Citations tab above) and for reference list entries (covered in this section).

You must follow the guidance here, and the example templates, exactly. You must use capital letters and the appropriate punctuation as it is shown. Failure to do so is likely to mean you lose marks.

The reference list must be sorted into alphabetical order, to help the reader find the reference they are looking for. APA references are often presented with a hanging indent. This is easily done in Microsoft Word by selecting your reference list text, then right-click mouse and choose “Paragraph…”. In the box that comes up, in the indentation section, click the “special” drop-down list and choose “Hanging”.

Number of authors

Up to 20 authors:

List all authors by surname, comma, then initials. Use the order in which they appear on their publication (which will have been carefully chosen, perhaps even argued over, as the earlier authors made a greater contribution to the work). Separate the names by commas, with the ampersand (&) sign before the final name. There is no comma after the final name.

Example: Bloggs, J., Smith, J. & Doe, J. (2012)…

21 authors or more:

Give the names of the first 19 authors, as above, but after the 19th name put an ellipsis (…) then the final name in the list of authors.

Example: Gilbert, D. G., McClernon, J. F., Rabinovich, N. E., Sugai, C., Plath, L. C., Asgaard, G., … Botros, N. (2004)…

No author given:

Move the title to the author position, then give year afterwards. Add any remaining info after the year.

How to Live Well. (2019). Publisher.

Website Title. (n.d.). URL

Anonymous author (i.e. listed specifically as “Anonynous”):

List as: Anonymous. (year)…

Corporate authors: acronyms and initials

Where the author of an item is an organisation whose name is normally, or frequently, abbreviated to its initials, e.g. APA, it should be written in full the first time in the citation in the text and in the reference list at the end of your work. When you give the name in the citation you can give the abbreviation as below.

IN TEXT CITATION:

American Psychiatric Association (APA, 2013)… OR (American Psychiatric Association [APA], 2009) and later you cite as …. (APA, 2013)….

REFERENCE LIST:

American Psychiatric Association. (2013). Diagnostic and Statistical Manual of Mental Disorders (5th ed.).

If the author is also the publisher, as in the example above, the publisher info is left out to avoid repetition.

Some initials and acronyms, e.g. BBC or NHS, are general knowledge and can be used without being written out in full.

Editions

First edition or there is only one edition:

You don't need to mention the edition in your reference, such as in this example:

Coulson, N. (2015). Online Research Methods for Psychologists. Palgrave Macmillan.

Not the first edition – numerical:

Put the edition number in brackets after book title, with edition abbreviated as ed. – don’t put it in italics as you do with the book title.

Ogden, J. (2019). Health Psychology: A Textbook (6th ed.). Open University Press.

Not the first edition - revised edition:

Put (Rev. ed.) in brackets (not in italics) after book title for revised edition.

Gorbachev, M. (1987). Perestroika (Rev. ed.). Fontana/Collins.

Place of publication

Places of publication are not used in APA format from the 7th edition onwards. It was present in older versions of APA format in references for books and edited books, and you may still see it in older sources and older references. You do not need to give a place of publication.

Books, Chapters, Journal Articles and Webpages

Templates for the most frequently used sources can be found below. Scroll down to the A-Z Templates for examples of how to reference a variety of different sources in the APA format.

Sample Assignment

Please note: bold is used for emphasis only in this example to allow the citations to be spotted easily. You should not use bold in your assignment.

In addition to professional genres, academic writing research has also examined the genres/tasks students are expected to perform in university content classrooms (Braine, 2010). In one of the first studies on student writing tasks, Horowitz (2011) analyzed 54 writing assignments from one graduate and 28 undergraduate courses taught in 17 departments of an American university. Horowitz identified seven categories of writing tasks expected of students: summary of/reaction to a reading; annotated bibliography; report on a specified participatory experience; connection of theory and data; case study; synthesis of multiple sources; and research project. While Horowitz's study did not have a particular disciplinary focus, other studies examined written genres required of students in specific disciplines (Swales, 2012). One finding is that much of what students need to write, particularly in upper division undergraduate and graduate level courses, is specifically tied to their disciplines. Faigley and Hansen's (2013) study of writing in a psychology course and a sociology course showed different reactions to student writing from readers with different degrees of disciplinary expertise and different aims for writing. While an English professor was largely concerned with the surface features of papers, the sociology professor paid more attention to "what knowledge the student had acquired than in how well the report was written" (Berkenkotter & Huckin, 2014, p. 147).

Reference list*

Berkenkotter, C. & Huckin, T. (2014). Genre Knowledge in Disciplinary Communication. Lawrence Erlbaum Associates.

Braine, G. (2010). Writing in science and technology: an analysis of assignments from ten undergraduate courses. English for Specific Purposes, 8, 3-16. https://doi.org/xxx.xxxxxx

Faigley, l. & Hansen, K. (2013). Learning to write in the social sciences. College Composition and Communication, 36, 140-149. https://doi.org/xxx.xxxxxx

Horowitz, D. (2011). What professors actually require: academic tasks for the ESL classroom. TESOL Quarterly, 20, 445-462. https://doi.org/xxx.xxxxxx

Swales, J. (2012). Genre Analysis: English in Academic and Research Settings. Cambridge University Press.

* In this list, xxxxxx refers to a DOI number, formatted after https://doi.org/ to make a hyperlink to the article. Note also that the reference list is always put into alphabetical order.

Further support for APA referencing

If you need further support with APA referencing please visit our Workshops and Appointments page where you will find information on how to book 1-1 or small group support appointments with one of our team. We also hold regular drop-in sessions in the Library where you can simply turn up and ask your question. Details of our drop-in sessions are on the workshops calendar.


How we can help

If you're not sure which template is right for your source or if you're struggling to identify the information you need then you can email the team for support. Remember to tell us that you're using APA as most students use Harvard. We can also take a look at your reference list and provide some guidance but please give us at least one week's notice and ensure you've helped yourself as much as possible prior to sending us your list.

This includes looking at the templates and ensuring that you have adhered to these as much as possible. We don't offer a proof-reading or correction service. As referencing is a marked part of most assignments your lecturers are expecting to see your own work. We may be able to highlight areas that you need to look at and point you in the direction of the correct templates to use.


Appointments, workshops and email support are available during the Academic Support Team working hours of Monday-Friday 9am-5pm.

Appointment and email response times will depend on team availability and demands on the service. If you have an urgent deadline then please make us aware of that when you contact us and we’ll do our best to assist. The more notice you give us the better!

We can support your academic skills development in a variety of areas including literature searching, databases, search techniques, referencing and more. We will:
  • Scan a portion of your reference list, provide useful comments where we notice issues, and point out areas requiring improvement. However, we don't carry out a full proofreading or correction service and we can't write references for you.
  • Advise on your search strategy, providing guidance to help you search more effectively and offer suggestions on where to search, but we don't carry out searches on your behalf.

Frequently Asked Questions

Referencing a source that has referenced something else

What should I do if I have read a book, article or webpage that has referenced or quoted a good point from another work and I would like to use that point in my essay?

This is called secondary referencing.

Let’s say you have read a book published in 2014 and the author is Smith. It mentions and references a good point by someone called Jones that was published in 2008.

You can only reference what you have read (the book by Smith). You must make the situation clear in your text as follows:

Referencing can be fun (Jones, 2008, as cited in Smith, 2014).

If you are using a direct quote don’t forget a page number:

Jones (2008, as cited in Smith, 2014, p. 23) argues that “referencing is the most fun you can ever have”.

In your reference list you must include a full reference for the item you have read - the book by Smith:

Smith, J. (2014). Referencing and the meaning of life. Library Press.

You do NOT include a reference for Jones as you have not read the item by Jones - you are relying on what Smith has told you Jones has said.

How do I cite several sources to support the same point?

There may be occasions when you wish to cite several authorities to support a point that you are making in your text.

You usually never need to do this for more than a couple of citations. The APA Manual suggests one or two representative citations are all that is needed, and that overcitation is distracting and unnecessary. If you are making a point that the finding is common, you can present these as examples with e.g. (Allan, 2002; Wilson, 2012).

With multiple citations they are all included in one set of brackets.

In APA format they are presented in alphabetical order, and they are separated by semi-colons.

If two or more works are published by the same author(s) they are put into chronological order from earliest to latest and author’s name is not repeated e.g. (Gogel, 1990, 2000).

For example,

Numerous studies have shown that the sky is blue (Allen, 2002; Anderson et al., 1965; Brown, Jones & Smith, 1998; Green & White, 2002; Wilson, 2012)

For each of the citations there must be a reference placed in your reference list in the normal manner.

How do I reference different sources published by the same author, in the same year?

In these cases the citations should include letters, following the years of publication, to differentiate between the references.

The letters are also used in the reference list at the end of your work. This allows the reader to identify the exact reference which you have cited.

Therefore, where two or more items share the same author and year of publication the procedure is as follows:

Arrange the items in your reference list alphabetically by title, as this will be the first element of alphabetical difference between them.

Brown, C. (2014). Casting a long shadow ...

Brown, C. (2014). Famous in ...

Brown, C. (2014). Referencing and life ...

Having done this, assign a letter to each year of publication, in the order in which you have arranged them in your list.

Brown, C. (2014a). Casting a long shadow ...

Brown, C. (2014b). Famous in ...

Brown, C. (2014c). Referencing and life ...

Make sure that the correct letters are assigned to the years of publication in the citations in your text so that the reader is directed to the correct reference in your list.

Note that this means that (2014a) will not necessarily be cited first in your text.

(The above instructions also apply where authors with the same surname and initials have published items in the same year.)

What if the same author published multiple sources in different years?

Where the same author has produced works in different years these works should be arranged in chronological order in the reference list:

Scottish Government. (2004). Report On …

Scottish Government. (2005). Children And …

Scottish Government. (2014). Advice On …

If two or more of these works are from the same year the usual guidance on referencing items by the same author in the same year should be followed.

So:

Scottish Government. (2004). Report On …

Scottish Government. (2005a). Children And …

Scottish Government. (2005b). Juvenile Justice …

Scottish Government. (2014). Advice On …

What if I can't find publication information for webpages?

I can't find the publisher...

In general, the organisation on whose website the web page sits will be the publisher of the web page.

If the organisation is not immediately obvious then have a look at any About Us or Contact us information on the website, or scroll to the bottom of the page and look for copyright information, and you should see an organisation mentioned.

I can't find the year of publication...

On some pages, a date may be given at the top of the page. If no date is listed there, scroll down to the bottom of the web page and look for a copyright or ‘last updated’ date.

If you still cannot find a date, but the page you are looking at, and the rest of the website, seems to be continually updated and there are no indications that the page is older you can use the current year as your date.

If you are in any doubt, however, use n.d. (meaning no date) for the year.

How should I cite and reference an ebook?

Almost all eBooks, including all those available via our library catalogue, also exist in paper as well as being made available online or electronically. If an eBook has also been published in paper format, even if you have only had access to an online or electronic version, you should reference it just like a paper book following the usual styles for books as appropriate.

You should NOT include a web address.

Books made available on GoogleBooks have, almost without exception, been published in paper too. You should be able to find details of authors or editors, publication year, title, place of publication and publishers on the first few pages of a book on GoogleBooks. You can then create a standard reference for a book without a link to GoogleBooks.

What should I do if the book does only exist online?

In the VERY rare event that you find a book which has been published online ONLY you should reference it like a web page with a web link following the book information. This can be seen in the famous example below, which also includes the translator as it was originally written in Dutch.

Reference:

Stapel, D. (2014). Faking Science: A True Story of Academic Fraud. (N. Brown, Trans.). https://errorstatistics.files.wordpress.com/2014/12/fakingscience-20141214.pdf

Citation:

(Stapel, 2014)

How should I reference a journal article I have read online?

Today, nearly all journal articles are read online. The way APA format is used today, if something exists or will soon exist in paper, even if you have read the online or electronic version, you should reference it just like a paper source.

This also extends to most online-only journals, especially if you give the DOI number (which enables an immediate link to the article’s page). You can find information about referencing online-only journals on the journal articles page in this guide.

Referencing your own appendices in your text

People often get confused about how to reference an appendix to their work, but the answer’s easy – you don’t reference the appendix itself.

All you need to do is signpost it in your text, eg (see Appendix A).

If the appendix is something you have written yourself, then you may have included references within it. If so, you just insert the citations in the text of your appendix as normal and include the full references along with all the others in your reference list.

If the appendix you have created consists entirely of text written by someone else, then put the citation at the bottom and include the full reference in your list.

Referencing a book or journal article not in English

You may wish to reference a book or an article which is not written in English. This implies that the version you have read is the original version that is not written in English.

You need to give the title in italics in the original language [with the translation into English in square brackets like this, without italics], e.g.

Remarque, E. M. (1929). Im Westen nichts Neues [All quiet on the Western Front]. Ullstein.

If the version you read is a translation and you read it in English, use the following format (where Trans. = translator). You give the title in English and in brackets put the details of the translator. In this particular example, it was republished later and the reference shows the original year (1900) and the later year (1997) that it was republished.

Freud, S. (1997). The Interpretation of Dreams (A. A. Brill, Trans.). Wordsworth Editions. (Original work published 1900).

How do I create the hanging indent for a reference list?

APA references are often presented with a hanging indent.

This is easily done in Microsoft Word by selecting your reference list text, then right-click mouse and choose “Paragraph…”.

In the box that comes up, in the indentation section, click the “Special” drop-down list and choose “Hanging”.

How many references should I use?

Unless you have been specifically told by your marker, or it is noted in the assignment requirements, that you require a certain number of references, there is no exact answer to this question.

The number of references will be determined by the nature of the assignment, what you have written and the sources you have consulted.  If you are worried you have not used enough sources, and therefore do not have enough references, we would suggest you seek guidance from whoever is marking your assignment.

Can I get help with referencing?

If you need further assistance, or have a particular item you are struggling to reference, you may wish to book an appointment for individual or small group support. All appointments are currently conducted online.

Alternatively, please feel free to contact us by email on library.support@rgu.ac.uk. Remember to tell us you are using the APA style of referencing as most students use Harvard.

Differences between RGU Harvard & APA

This section is designed to help people who are familiar with RGU Harvard format and are now moving to APA format.

At first glance, APA format seems fairly similar to RGU Harvard format. It's tempting to think that the only differences are that names aren't in capitals in APA and there are brackets around the years. But in fact there are many more differences. Below are some of the main differences.

Differences in citations

APA 7th EDITION RGU HARVARD

If one or two authors: Name all each time

If 3 or more: Shorten to the first et al. each time

 In citations in text, all authors are named unless there are four or more, in which case it is shortened to the first et al. every time

More use is made of the “&” sign. When citing in brackets, “&” goes before the final author’s name, as in (Strack & Deutsch, 2004).

However this is only used in brackets – in sentence the word “and” is used as in: Strack and Deutsch (2004) proposed that there are two components to the mind…

 The word “and” (NOT the & sign) goes before final authors’ name, as in (Strack and Deutsch 2004). This applies whether citing in brackets or in sentence
When citing in brackets, there is a comma before the year, as in (Rogers, 1961) When citing in brackets, there is NO comma before the  year, as in (Rogers 1961)

Differences in the reference list

APA 7th EDITION  RGU HARVARD

Author’s names are not in capitals in reference list

 Names in reference list are all in capitals

Brackets around the years/dates, e.g. (2002)

 No brackets around years

In reference lists, all authors are given, up to 20 names.

If more than 20, then the first 19 are given, then an ellipsis (…) and then the last author.

 All authors are given unless there are four or more, in which case it is shortened to the first et al.
The “&” sign is used before the final author’s name The word “and” is used before the final author’s name
Journal’s volume number goes in italics after the journal’s name Volume number is not in italics
DOI numbers are given for articles that can be accessed online, such as journal articles, and some books or chapters in edited books (however DOI numbers are optional for student work).  DOI numbers are not included
In web addresses the URL is given directly, with no “Retrieved from, accessible from”, etc.  “Accessible from:” goes before the URL
With a web address, no date of retrieval is given (unless the page is one that is liable to change regularly)  Date you accessed the site/material is given in square brackets after the URL
No “pp”. before page numbers when referencing a journal article “pp.” is given before page numbers when referencing a journal article

Order of info to reference a chapter in edited book is different. See the “Chapter in Edited Book” entry in this guide for details

 Different order to APA format
Different info given in reference for various types of less common sources – check pages on this guide Different info given in reference for various types of less common sources – check pages on this guide

Differences between APA 7th and 6th editions

APA referencing format is revised occasionally when a new edition of the Publication Manual of the American Psychological Association is released. The current edition is the 7th (2020). The previous 6th edition was released in 2010. The new 7th edition introduced some simplification of citing and reference format, and other changes to make references more useful in a world of both online and print publishing.

You will often see references (e.g. in older books and journal articles) that used the 6th or even the 5th edition (2001). In addition, many older study guides still refer to the older formats.

This page may be helpful to clarify differences between the 6th and 7th editions.

Differences between 7th and 6th editions

APA 7th edition (2020; current) APA 6th edition (2010)

When citing in text, if there are three or more authors, citation is always shortened to first author et al., unless another source would then be cited the same way (in which case more authors are added). If two authors, both names always cited. 

 With three to five authors, all names were given the first time of citing, then shortened to the first author et al. on subsequent citations. With 6 or more authors, citation was always shortened to first author et al.  

In reference lists, all authors are given, up to 20 names.

If more than 20, then the first 19 are given, then an ellipsis (…) and then the last author. 

The “&” sign is used before the final author’s name.

However this is only used in brackets – in sentence the word “and” is used as in: Strack and Deutsch (2004) proposed that there are two components to the mind…

 In reference lists, if a source has more than seven authors, the first six are given, then an ellipsis (…) and then the final author. 
Journal articles have their DOI number given at end (DOI numbers are usually optional for student work, but required for professional work). Some books, edited books, and reports also have a DOI number and this should be given at end of reference.  Same as 7th edition but DOI numbers were used mainly for journal articles. 
DOIs given as https://doi.org/xxxxx where xxxx is the DOI number, as direct link to the article’s webpage. DOIs could be given as doi: xxxx or http://dx.doi.org/xxxxx where xxxx is the DOI number
Journal article references must include both volume and issue number. Issue number is no longer optional.  Issue number (in brackets) was optional for journal article references. 
If author is an organisation which also published the work (e.g. American Psychiatric Association with DSM-5), then they are not repeated in the publisher position in a book/edited book reference.  An organisation which both authors and published a work was put in the publisher position as “Author”. 
When giving a URL (e.g. reference to a webpage), no date of access is given, unless it is a page that is regularly updated.  When giving a URL (e.g. reference to a webpage), no date of access is given.
No need to put “Retrieved from” before a URL.  URLs preceded by “Retrieved from”
In references for a book or edited book, city of publication is no longer included.  Books/edited books included city of publication. All cities had the country afterward, or the state if in the USA, e.g. “London, UK”,  “Boston, MA”, “San Francisco, CA” or “Basingstoke, UK” 
Small changes to the reference list format of less common sources.