Kirsop Labs

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Citations, refs and bibliographies

Recently, a student told me that scientific writing for reports and literature reviews was the hardest part of the course, especially for non-native English speakers.

For undergrads and postgrads alike, getting your citations and bibliographies formatted correctly seems to be a common area of weakness. So here’s a (not so short) guide to help explain some of the rules and get your bibliography formatted right first time. Your next report or literature review will be guaranteed to look as professional as a published journal article!

An article on referencing styles is never going to float anyone’s boat. This I know. But use this guide with the style sheets provided in the links, and you’ll be experts (I promise) before your next assignment is due.

First – Some Common Mistakes

A common mistake made by students is overuse of “direct quotation”. Okay, so this is done as a way of avoiding plagiarism. Technically, it’s not exactly wrong, but neither is it good writing practice. It’s much better to make sure all sources of information are cited (and referenced) correctly.

Another common error is the misuse of punctuation. Commas, semi-colons, colons and periods are very specific to the style you use, and not meant for random distribution. These points are both discussed further on.

So It Begins…

The correct use of style, structure and formatting in your writing is so important if you want to produce a high standard of work. I deliberately haven’t included examples showing the layout of every single type of journal article reference. That’s what the links provided are for, so I suggest you refer to those while you read on. Even if you don’t read any further, please use these links before you start your next report or literature review.

Links #1 and #2 below will take you to the recommended style guides for chemists, and link #3 is an invaluable online resource, for locating full references and accurate bibliographic information.

So download the following:

1. Royal Society of Chemistry (RSC) Style Guide

2. American Chemical Society (ACS) Style Guide

and access this site:

3.  CAS Source Index (CASSI) Search Tool

The examples given in style guides #1 and #2 show you how to set out reference sources; journal articles, reviews, web sources, unpublished work, books, or something else that you wish to cite. Get it right from the start and you’ll save yourself a lot of pain and grief later on.

Universities don’t tend to adopt any single particular style, but they do stipulate a preference according to your subject. In chemistry, it’s suggested you follow a universal style guide from either the RSC or ACS, both of which are used by chemists around the world. The important thing is that you’re consistent throughout your work. Never mix styles! It could cost you dearly in your overall grading if it’s part of an assessed course.

So make it easy on yourself and follow these guidelines:

  • Undergraduates should use RSC or ACS style for reports and literature reviews
  • Postgraduates – for a thesis, review or original article, check with your supervisor, or use the specific style adopted by your intended journal

 A Wee Bit of Background

You might wonder where these rules all come from? Well, each publishing house has their own preferred style for the journals they publish. Have a look at journals by Elsevier, ACS, RSC and Karger. Of course there are many other major publishers, and you’ll have accessed these before. If you look at the citations and bibliographies from journal articles (papers), you’ll see at a glance how different journals use different layouts.

There are standards to follow and you need to be aware of the rules. Unfortunately, this is where students can get it wrong. It’s all too easy to mix different styles together when you don’t realise there’s a standard with rules to follow.

Citations, Refs and Error-Proof Bibliographies

So now you’ve decided which style you want to use. How do you apply it to your work? You use a Reference Manager of course.

By using Ref Manager software, your final reference list gets compiled at the same time as you ‘cite while you write’. This saves you an enormous amount of time, and should result in an error-free bibliography.

Citations (referencing in the text)

Each time you refer to published work you acknowledge that work as belonging to someone else. You do this by including ‘citations’ throughout your own work, and you may often hear this referred to as ‘references’. This is really incorrect terminology, although we all do it. To be correct, you ‘cite’ the literature you are discussing, but you include a literature ‘reference’ in the Literature Cited section, or Bibliography, which appears at the end of the work.

This ‘reference’ contains information needed to locate and read any ‘cited’ literature. If you don’t cite your sources, then you’re saying the work actually belongs to you and could be interpreted as plagiarism. You can download a pdf file of the university document Plagiarism Student Guidance which has helpful advice.

How to Cite as you Write

Each reference to published work is given a number, and the number appears in the text where the work is discussed. This is usually as a superscript or within brackets on the same line as the text, but never both. Have a look at the following examples. Make sure you use the correct one for the style you’ve chosen.

Example 1: To overcome this kinetic barrier, the reaction between the flavin prosthetic group of the flavoprotein and dioxygen proceeds via a step-wise transfer of electrons.3

Example 2: To overcome this kinetic barrier, the reaction between the flavin prosthetic group of the flavoprotein and dioxygen proceeds via a step-wise transfer of electrons.[3]

Example 3: In 2008, Mole et al.21 described a correlation between the onset of MOF and levels of 3HK in serum, while Melvin et al.22 developed this further.

Example 4: In 2008, Mole et al. [21] described a correlation between the onset of MOF and levels of 3HK in serum, while Melvin et al. [22] developed this further.

To write it in the following way is wrong:

Example 5: In 2008, Mole et al. described a correlation between the onset of MOF and levels of 3HK in serum, while Melvin et al. developed this further.21,22

Example 6: In 2008, Mole et al. described a correlation between the onset of MOF and levels of 3HK in serum, while Melvin et al. developed this further.[21], [22]

This would mean that both papers were saying both things! Examples 5 and 6 are clearly ambiguous and incorrect.

When you use a single reference source e.g. journal article or book chapter, the citation number appears at the end of a sentence after the full stop (no space before the citation number), or in the body of the text where you make the relevant point.

When you have several references within one sentence, each source needs its own citation and reference number. The citation (and corresponding reference) numbers are made in the text, at the place where you discuss the published work.

When to Use Italics

The phrase “et al.” is Latin and always shown in italics, as are other commonly used abbreviations, such as via, in vivo, e.g., i.e., etc. Using “et al.” means ‘and other people’. This allows you to quote the lead author’s name only – Mole was the first author of the paper, but didn’t work alone.

Remember to Keep Them in Order

Citations are always sequential. Each reference in your bibliography is numbered in the order that it appears in the text. The first one you cite will be #1, and never 12, 25, etc. If you add references later while revising your work, you need to re-number everything. For the sake of your sanity don’t attempt this manually! This is where a Reference Manager system really is your best friend.

If you refer to the same article more than once, use its original citation number each time. Don’t give it a new number. If you need to reference several sources at once, list the numbers sequentially. Note there is no space between the numbers 25,26 below.

Example 7: Imbalances have been associated with many infamous and topical neurodegenerative disorders such as multiple sclerosis,24 Alzheimer’s disease,25,26 and amyotrophic lateral sclerosis.25

This rule also applies to figures and diagrams you use from published sources. Every figure, image or table, needs to be cited and captioned like the example below (Figure 10).

Just a small point for postgrads – if you’re writing a journal article for a peer-review publication, some require table and figure legends in a different font from the text so check the journal criteria.

For university assessed work, this may not be relevant and will dependent upon the assessor’s criteria for marking. Might be worth checking though, especially if it could result in lost marks.

Reference Lists and an Error-Free Bibliography

Right, so you’re now at the end of your report, literature review or thesis. You’ve used a Reference Manager like Mendeley with recommended style guides from RSC or ACS. Great! Nothing can go wrong with how your bibliographical list is compiled if you’ve inserted the information correctly into your Ref Manager.

Your references will be laid out correctly if you’ve followed these guidelines so far. And just to make sure – bear these points in mind when you’re checking your final bibliography for errors.

  • Journal Articles

Remember, some journals require the title of articles to be included, while others don’t. For assessed work, check with your supervisor if they have a preference. I can guarantee the answer will probably be – “no preference, just be consistent”. Different styles show reference information in different ways; particularly with author names and initials and the use of punctuation.

  • Authored Books

Have a look at these examples where the entire book is written by the named author/s:

RSC Style:  INITIALS. Author’s surname, Title, Publisher, Place of publication, Edition (if not the first), Year, Pages.

You’ll see that there are commas (not semi-colons) between author names, and the abbreviation for ‘edition’ is ‘edn’, (not ed.).

ACS Style:  Author’s surname, INITIALS. Title, Edition; Publisher: Place of publication, Year.

Referencing books is different from referencing journal articles and reviews. See how the abbreviation for ‘edition’ is different between the RSC and ACS styles, and the author’s name and initials are reversed. There’s also a colon between the publisher name and location in the ACS style. The order isn’t the same for both, and check the style guides to see where italic and bold font is used.

  • Edited Books

Sometimes there may be editor/s instead of (or in addition to) author/s. You need to know which abbreviations to use (ed., eds., or something else?). Pay close attention to the style guides.

  • Theses, Reports and Online Sources

How about when the publication you want to use is a health information leaflet from a medical communications company? Would this be written in the style of a book, or an article, or something else? How do you layout a reference for a thesis? A Conference Report? A Conference Abstract?

Check the RSC and ACS guides provided in the links. You should find it all there. Still can’t find the right example?

• Use a search engine. Something similar will have been referenced before so you can check what style and layout the author used.

• Ask someone – your supervisor – your friends – a lecturer – a postdoc – ask me! I’ll find it for you.

YouTube has lots of videos showing you how to write and cite correctly, just use ‘referencing and citations’ in the search bar. Okay, so it’s not Netflix, but for this purpose they’re pretty useful.

Final Checks Before Submitting

  • Each citation number in the text needs to appear in the reference list (bibliography), complete with publication details of where to find the full article or source of information.
  • Pay special attention to the format and punctuation used for difference resources, such as journal articles, books, web sources, etc.

That’s it. You’re done!

Acknowledgement: Thanks to Lindsey Robinson for her contribution to this article.


Co-founder of the KirsopLabs project, and Editorial Manager of Neuroendocrinology, a peer-review Medical Sciences journal. Writing for a science blog is a great way for students to get published early in their career and great for a CV. Drop me a line if you'd like to discuss how to get involved with the KLabs project.

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