How to cite and reference


  • There are many reasons to cite and reference in your work. It’s good practice, it prevents plagiarism and it can help to substantiate your arguments.
  • You should cite and reference when an idea or data does not belong to you.
  • Make sure you make note of certain information for each source that you cite and reference.
  • There are many referencing systems out there so pick the right one.
  • Reference management systems are a handy tool so it’s always worth learning how to use one early on.
  • Check your citations and references for any mistakes, avoid second hand citing, remain consistent with your referencing and aim to use only the most reliable sources.

It can be challenging if you’ve never had to cite and reference various sources before. Especially when you don’t know how it’s done properly. It’s an essential skill to have in higher education and doing it incorrectly can even decrease your assignment grades. So, it’s worth learning how to do it properly early on. But first, let’s look at the difference between citing and referencing. They are often used interchangeably but technically they don’t mean the same thing. A citation appears within the body of the text mentioning the source in the form of the author’s name and year of publication in parentheses or a number either enclosed in parentheses, square brackets or in superscript. The associated reference appears in the reference list or bibliography usually at the end of the document including further specific information on that cited source.

Why is it important to cite and reference?

Here are some of the main reasons why it’s important to cite and reference in your work:

  • Citing and referencing gives credit to other authors for their work and contributions. It’s always good practice to give credit where credit is due and is a courtesy that is expected of every author.
  • You avoid plagiarism.
  • It will help to substantiate your arguments. Using a credible source or even multiple credible sources to strengthen your own arguments just gives you more credibility.
  • Readers can see how up to date your information is.
  • It demonstrates that you have surveyed the literature and done your research.
  • Your readers have the freedom and ability to further investigate your claims if they so choose.

When should you cite and reference?

You should always cite and reference the ideas and data that you have taken from elsewhere in the literature. Now, I recognise that most ideas that are thought up have coincidently been similar or even the same as someone else’s. The only way to be sure that no one else has come up with your idea already is to survey the literature as thoroughly as possible. How much is thorough? It’s subjective. You will likely know all of the best places to look or know someone who does. But just because you can’t find it doesn’t mean it’s not there. It’s forgivable if you genuinely cannot find anyone else who has published your idea already. We are human after all. Those who assess your work may or may not spot this either. This is where intellectual honesty comes into play.

If you know that the idea you are presenting is not yours then credit the source. Moreover, if your idea is similar to another author but different in other ways then point out the differences but still cite and reference said author. That’s also intellectual honesty. This avoids plagiarism. I have discussed the penalty for plagiarism in my blogs ‘How to write coursework to boost your grade’, ‘Writing a quality dissertation’ and ‘PhD viva: the defence’. Avoid plagiarism at all cost.

The case is a lot clearer when it comes to data. If the data you present is not yours and is published elsewhere then you must cite and reference the source. Passing off the data of others as your own can land you in trouble quickly. It won’t be hard for your readers, especially the ones quite familiar with the literature, to spot this.

Information you need for referencing

It’s not as straightforward as giving the name of a book or a weblink to an article. There is a standardised convention for referencing various sources. It all depends on the type of source and reference system that you employ. In general, for each source that you cite and reference you need to make note of the following:

  • initials and surnames of all authors;
  • year of publication;
  • title of the publication;
  • for a journal article, the journal name, volume number, issue and the first and last page numbers of the article;
  • with a chapter in an edited book, the book title, initials and surnames of all editors, publisher name, place of publication and the first and last page numbers of the chapter;
  • for a web page, names of either the authors or organisation, the date the web page was published online, the web page title, the web address and the date of access.

This appears to be a lot of information to recollect, but as you become more adept at writing you’ll become better at gathering this information or knowing where to look. However, sometimes it’s not possible to find all the information you need. For example, some web pages don’t display their publication date in which case it’s fine to omit this information. But if you find that you’re unable to get enough information on a source that it would be difficult for readers or publishers to accept then consider acquiring the same information from another source that has all of its details readily available.

Note that a book publisher and printer are not the same thing, but they can be easily mistaken for each other. The name of the publisher is found on the main title page of a book and sometimes on the spine.

Referencing systems

The two main referencing systems tend to be Harvard and Vancouver. I briefly mention both types in my other blog ‘How to write coursework to boost your grade’. If you’re writing a journal article, I recommend consulting the Guide for Authors for your target journal on which referencing system to use. However, if you’re writing a dissertation/thesis or another type of assignment, then check with your institution on which type of referencing system they’d recommend that you use. Let’s have a closer look at both of these referencing systems in turn.


This system is commonly used in the natural sciences and social sciences. For the Harvard referencing system, in-text citations include the author name and publication year in parentheses for that source. Here’s an example of an in-text citation of a journal article:

Pd-based alloy membranes have the potential to separate hydrogen from a hot gas mixture achieving high purity levels (Al-Mufachi, et al. 2015).

Note that ‘et al.’ is a Latin abbreviation for ‘and the others’. Typically, this abbreviation is used when there are more than two authors associated with a particular source. Another way of doing it could involve mentioning the author(s) in the text with only the publication year enclosed in parentheses:

Al-Mufachi et al. (2015) mentioned the potential of Pd-based alloy membranes to separate hydrogen from a hot gas mixture achieving high levels of purity.

If you want to make a direct quote, then you’ll need to include the page number for your readers to locate the exact quotation:

Al-Mufachi et al. (2015: p. 541) concludes that “dense Pd-based metal membranes offer a convenient way to separate hydrogen from a hot gas mixture”.

You should also cite and reference the source of diagrams and data used in tables. If you’ve included a straight copy of a figure in your work then you can cite it like so:

Figure 1.1. The various diffusion models for hydrogen in metals (from Kehr, 1978: p. 197).

If you present data in a table that is sourced from somewhere else then you can cite it like so:

Table 1.1. Properties of the various types of hydrogen-selective membranes (data from Kluiters, 2004: Table 1)


This is the referencing system I primarily used throughout my time studying and working at university. The Vancouver referencing system is commonly used in disciplines such as medicine and the physical sciences.

In principle, the Vancouver referencing system is the same as the Harvard referencing system however it only differs in style. The Vancouver referencing system makes use of a sequential numbering system for the in-text citation. The numbers will either appear in parentheses, square brackets or superscript. Examples of each in-text citation would look like this:


Pd-based alloy membranes have the potential to separate hydrogen from a hot gas mixture achieving high purity levels (1).

Square brackets

Pd-based alloy membranes have the potential to separate hydrogen from a hot gas mixture achieving high purity levels [1].


Pd-based alloy membranes have the potential to separate hydrogen from a hot gas mixture achieving high purity levels1.

Another thing to bear in mind is citing multiple sources. If you cite more than one source the numbers assigned to each source are listed sequentially separated by commas from lowest to highest number. If there are more than two sources cited which appear in the text sequentially then the citation is shortened using a hyphen. Sources that are not cited consecutively in the text can be listed and separated with a comma. You can see many examples of these citations in the introduction section of the PDF version of my original research article here.

In addition to the full reference details being inserted at the end of the document, you can also insert this information at the bottom of a page. This is known as a footnote.

Reference list

At the end of the document, you must provide further detail of this source in the reference list. The formatting of information in the reference list is essentially the same for both referencing systems. The only difference is that the sources are listed alphabetically in the Harvard referencing system, whereas the sources appear in the same sequence as they appear in the main text for the Vancouver referencing system. Below are some examples of how different types of sources should appear in the reference list. Pay particular attention to the information that needs to be included, the order of information, punctuation, capitalisation and typeface.

Journal article

When referencing a journal article, you have to include the author name(s), article title, journal name, volume number, issue (if given), publication year as well as first and last page numbers of the article. Author names can be listed with the surname first followed by the initials or vice versa. The initials can even feature a full stop between each initial. If your work is to be published then even the order of information listed in the reference list can be slightly changed depending on the publisher’s preferences. Below is an example:

Al-Mufachi NA, Rees NV, Steinberger-Wilkens R, Hydrogen selective membranes: a review of palladium-based dense metal membranes, Renewable and Sustainable Energy Reviews 47 (2015) 540–551.


For referencing a book, you must include the author name(s), book title, place of publication, publisher name and publication year. Here’s an example:

Mulder M. Basic principles of membrane technology. Dordrecht: Kluwer Academic Publishers; 2000.

Edited book

An edited book is a collection of scholarly or scientific chapters written by various authors. The idea is similar to a book reference except more information is needed. You must provide the chapter author, chapter title, editor name(s), book title, place of publication, publisher name, publication year as well as first and last page numbers of the chapter. Here’s an example:

Kehr KW. Theory of the diffusion of hydrogen in metals. In: Alefeld G, Völkl J, editors. Hydrogen in metals I. Berlin: Springer Verlag; 1978. p. 197–226.

Web page

Referencing web pages can be troublesome sometimes as it’s difficult to find all of the necessary information like author name and date of publication. Nevertheless, where possible state the author name(s), date of publication, web address and access date.

Al-Mufachi NA (29/07/2020) Peer review: how it works. Accessed 23/09/2020.

Reference management system

Reference management systems (RMSs) are an amazing invention. Rather than you having to format and input each individual citation and reference manually, an RMS will do this for you automatically. There are plenty of RMSs to pick from such as Endnote and Mendeley, to name a few. They work by importing information about a source into the RMS. Then you can use that RMS to insert a citation and its associated reference into a Word document, for example.

Information about a source can be found in a citation file which you download from the internet. You can then open this file to import all of the source information into the RMS. Using the RMS, you can view and edit the source information and even create a database of references. This is especially useful when you have hundreds of references to contend with. You can even choose from a variety of referencing systems to use in your document. If you move or delete citations and references in your document the remaining citations and reference list automatically update to reflect any changes. Can you imagine having to update and reorganise hundreds of citations and references manually? It’s a painful task.

Invest time, as early as possible, in learning how to use an RMS as this will make your life exponentially simpler. There are plenty of resources out there to help you get started. I once attended an Endnote workshop and I spent time experimenting with the software in my own time as it’s quite intuitive in places. There are likely countless tutorial videos online that can also teach the basics, so what are you waiting for?

Downloading citation files

You can retrieve citation files online using Google Scholar. Google Scholar is a special search engine designed to retrieve scholarly literature from various disciplines. I go into more detail in my blog ‘Writing a quality dissertation’ about how to use Google Scholar to download a citation file so check it out.

You can also find citation files on journal websites. Like with Google Scholar, you can export the citation files in various formats to suit your RMS. Below is a screenshot showing an example of where you can find a citation file for a journal article. Citation files are readily available online at various locations. Just make sure you double-check the reference details once you import the information into your RMS. Sometimes, you can find glaring mistakes.

A screenshot of the ScienceDirect website showing how to export a citation file to reference a source.
You can use websites like ScienceDirect to export your citation files. It’s one of many places where you can find these files.

Check your references

Proofread and edit

When I was compiling my reference library for my PhD dissertation, I spent a considerable time proofreading and editing hundreds of citations and references. Just like the main body of text in any type of document you do not want any spelling, grammar or punctuation mistakes appearing in your citations and reference list. The information found here has to be accurate as your readers, who may be researchers, will refer to your reference list to study your sources.

Don’t second hand cite

When you are reading from the literature you will likely come across cited information in a particular source that you want to refer to in your work. The cited information is referred to as the primary source and the source where you have read this cited information is the secondary source. This is known as second hand citing. Essentially, you are relying on someone else’s interpretation of a source as opposed to interpreting it yourself. This can be risky. From time to time I get notified of authors citing my work and I sometimes read this source to see how they have interpreted my publication. On occasion, I find that some authors have completely misinterpreted my source. Whether this has been done on purpose or not is unknown. Sometimes my source has been incorrectly used to support an unrelated argument. I’m left thinking, ‘I never said that!’.

The truth is that the peer-review process does not involve checking each individual citation for accuracy. It would take almost an eternity. So, for that reason, it’s better to avoid second hand citing and always read the primary source. Check out my blog ‘Peer review: how it works’ if you want to know how the peer-review process works.


I’ve always said that consistency is king. Whatever referencing system you decide to choose stick with it throughout your entire document. It will only confuse your readers if you decide to shift between the Harvard and Vancouver referencing system.

Moreover, if you decide to go with the Vancouver referencing system make sure to use only one style of in-text citation whether it be parentheses, square brackets or superscript numbers.

Additionally, use the same text format in the reference list for each type of source. Whether it’s a journal article, book, edited book or website, make sure that you list all the key information in the correct order, with the right punctuation, capitalisation and typeface every time.

Quality and reliability of a source

From my own experience, I always cited sources like journal articles, books and edited books. Normally, these types of sources have been peer-reviewed and go through some quality control process. So, information residing in them are likely to be more accurate and reliable. Moreover, they’re easily retrievable and accessible. For this reason, I rarely cited web pages as their content can change all the time and can be removed too. Likewise, referencing a personal communication can be tricky as it’s difficult to prove and retrieve this source.

Where possible, I like to cite well-known and reputable sources. This could include journal articles and textbooks. I try to go for highly-cited sources as this is usually a marker for a high-quality reliable source. But not always, so use your best judgement.

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Naser Al-Mufachi
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