In-Text Citations and References Sections

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Today I’m very excited to bring you our first guest post on this blog.  It was written by my colleague Dr. Evan Davies and it’s all about how to handle your citations and references correctly in a formal report or thesis.  I’m sure you will find this information extremely useful!  Thanks Evan for sharing this great advice with us!  

Evan DaviesProper formatting is very important!  Formatting rules apply both to citations in the body of your text and to references at the end of your text.  For good or bad, researchers equate your consistency in formatting with the rigour of your work. In other words, if your referencing is sloppy, your research probably is too.  (Obviously, having correct spelling and grammar is even more fundamental than proper formatting – if you have poor grammar and spelling errors, it’s really “game over” for your work.)

This document explains proper formatting approaches for in-text citations and references sections.

How to Cite Sources in the Body of a Report or Article

You must choose a consistent approach to citing sources. In-text citations are typically very straightforward with only a few changes from one formatting style to another. There are two common approaches: “author, year” citations, and “numbered” citations. Each researcher has his/her own preferences; however, I prefer the “author, year” approach, which allows the reader to identify the source of the information cited quickly and easily without referring repeatedly to the references section. 

1. Author, Year Citations

There are several rules for “author, year” citations:

1)      List only authors’ last (i.e. family) names.  Do not include initials or first names.

2)      List only the first author for papers with one, or three or more, authors.  Single-authored papers are straightforward.  For papers with two authors, list both author’s last names.  For papers with three or more authors, use “et al.” after the first author’s name.

3)      In the unusual case that you have the same first author for different papers published in the same year, add a letter (or other identifier) after the year to differentiate the papers.

4)      Where you are using a direct quotation, include a page number after the publication year.

A few additional points follow.  The use of a comma between the author name and the year is optional.  Also, some authors use a colon between the year and page number, others use a “p.”, and still others write “page”.  It does not matter which convention you choose, but once you have chosen a convention, use it consistently throughout the text.  Here are a few examples of variations: (Jones, 1992) or (Jones 1992); (Smith and Jones, 1992) or (Smith & Jones 1992); (James et al. 1996, page 123) or (James et al., 1996: 123) or even (James and coworkers[1- see footnote] 1996, p. 123).  And for two publications from the same year by Wang and coworkers, write (Wang et al., 2008a) and (Wang et al., 2008b) – and then make sure that your references section includes both papers with “a” and “b” after the appropriate reference.

You may also need to refer to more than one source to substantiate one of your arguments.  For example, you may want to provide some evidence that is supported by several different authors, or refer to similar arguments in a few papers authored by different people.  In such cases, you can list several papers at the end of a sentence like this: “According to several recent studies (Jones, 1992; Smith and Jones, 1992; Wang et al., 2008a), the top speed of migrating songbirds reaches…”.  Finally, if you refer to the same source several times in a single paragraph, and there are no other sources between each of these references to a single source, you can use the term “ibid.”

Below are a few examples (in bold type) found conveniently in one publication[2]:

Modeling has often been relegated to the academic and professional world, but, in the proper context, it can also be useful as an interactive and educational tool for non-technical individuals. ‘‘System dynamics can promote public participation by showing that our choices can affect the direction the future takes’’ (Stave, 2002, p. 165). System modeling enables the trial of policy options without having to accept the consequences (Shultz and Holbrook, 1999), as well as quick feedback from these options (Stave, 2002).

2. Numbered Citations

In contrast with the “author, year” format, numbered citations do not provide the publication year in the text, and authorship is also typically not provided in the body text.  For these details, readers must turn to the references section, which can lead to a lot of page flipping!  However, numbered citations save space and reduce clutter in the text, which – I think – are the sources of their attraction.  With small differences between journals, numbered citations have the general appearance of the samples below[3] (citations shown in bold type):

1)     There is increasing concern over the connection between fossil and industrial emissions and terrestrial ecosystem emissions, and the implications of this interaction for climate change mitigation strategies. Several research studies (1–8) have shown that…

2)     Among the different techniques widely used nowadays, wavelet and multi-resolution [11,16,29] analyses propose a time-scale transformation of the signal that accounts for flow variability. These methods have already been applied in different fields of hydrology ([9,14,22,23,25–27] and references therein).

How to Create a References Section

You must choose a consistent approach to citing references.  Make sure all the information required for someone to locate your source is available in your references section.  Each of the following components MUST BE PROVIDED, unless you have a very good reason for omitting them: author name, editor name, publication year, chapter/article/web page title, journal/book/report title, journal volume (and issue) or book edition or report number, doi reference (for some journals), publisher, publisher location, page numbers.  There are very few exceptions: no publisher name (e.g. Elsevier) or publication location (Dordrecht, the Netherlands) is required for journal papers, and authorship for web pages can sometimes be “anonymous” or by the name of an institution or government ministry (e.g. World Health Organization, or Natural Resources Canada).  The onus is on you to find all the pertinent details, and you may have to do some digging, by visiting publisher websites, looking for similar publications etc., if all the required information is not present in your reference.

Reference Styles

There are many styles available for citing academic literature.  For example, a journal paper written by Arendt et al. in 2002, could be cited as:

  1. Harvard format:

Arendt, AA, Echelmeyer, KA, Harrison, WD, Lingle, CS, and Valentine, VB, 2002, Rapid wastage of Alaska glaciers and their contribution to rising sea level, Science, vol. 297, no. 5580, pp. 382-386.

  1. Science journal format:

A. A. Arendt, K. A. Echelmeyer, W. D. Harrison, C. S. Lingle, V. B. Valentine, Science 297, 382 (2002).

  1. Advances in Water Resources journal format:

Arendt AA, Echelmeyer KA, Harrison WD, Lingle CS, Valentine VB. Rapid wastage of Alaska glaciers and their contribution to rising sea level. Science 2002;297(5580):382-386.

Some journals require abbreviated journal (and even organization/publisher names, on ocassion) titles.  A good source for standard abbreviations of common words is the ISSN List of Title Word Abbreviations (the LTWA database), which is accesible at

Internet sources are even more confusing because the required elements for citation are less standardized.  An example, using the same three formats above, is shown below:

  1. World Health Organization (WHO) and United Nations Children’s Fund (UNICEF), 2005, Sanitation Data at Global Level, WHO/UNICEF Joint Monitoring Programme, Available from, last accessed October 29, 2008.
  2. World Health Organization (WHO), United Nations Children’s Fund (UNICEF). Sanitation Data at Global Level. Joint Monitoring Programme. 2005. WHO/UNICEF Joint Monitoring Programme. 29-10-2008. [Note: this formatting is probably incorrect, since the URL is missing]
  3. World Health Organization (WHO), United Nations Children’s Fund (UNICEF) [Internet]. Sanitation Data at Global Level. c2005 [cited 2008 Oct 29]. Available from:

Examples based on the Harvard style

I like the Harvard format, which is one of the most straightforward and earliest referencing formats developed.  Using the Harvard format for a journal looks like this,

  1. Single author: Arnell, NW, 1999, Climate change and global water resources, Global Environmental Change, vol. 9, p. S31-S49.
  2. Two authors: Ahmad, S and Simonovic, SP, 2004, Spatial system dynamics: New approach for simulation of water resources systems, Journal of Computing in Civil Engineering, vol. 18, no. 4, pp. 331-340.
  3. Fewer than seven authors: Arendt, AA, Echelmeyer, KA, Harrison, WD, Lingle, CS, and Valentine, VB, 2002, Rapid wastage of Alaska glaciers and their contribution to rising sea level, Science, vol. 297, no. 5580, pp. 382-386.
  4. More than seven authors: Schröter, D et al., 2005, Ecosystem Service Supply and Vulnerability to Global Change in Europe, Science, vol. 310, pp. 1333-1337.

For a book, you can use:

Forrester, JW, 1961, Industrial Dynamics, John Wiley and Sons, Inc., New York, N.Y.

Canadell, JG, Pataki, DE, and Pitelka, LF, 2007, Terrestrial Ecosystems in a Changing World, Springer-Verlag, Berlin.


For a book chapter:

Claussen, M, 2001, “Earth System Models,” Chapter 10 in Understanding the Earth System: Compartments, Processes and Interactions, Ehlers E, and Krafft T, eds., Berlin, Germany: Springer, pp. 147-162.

Christensen, JH et al., 2007, “Regional Climate Projections,” Chapter 11 in Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Solomon S et al., eds., Cambridge, UK: Cambridge University Press, pp. 847-940.

For an internet source:

United Nations Department of Economic and Social Affairs (UNESA), 2006, World Population Prospects: the 2006 Revision Population Database, Available from, last accessed November 12, 2006.

Food and Agriculture Organization of the United Nations, 2010, FAOSTAT Database Query, Food and Agriculture Organization of the United Nations, Rome, Italy. Available from, last accessed May 25, 2010.


  1. This last form, “and coworkers” (or other variants of this sort) is very uncommon and I would recommend against its use.  However, it is provided here for completeness.
  2. Williams, A., Lansey, K., and Washburne, J. (2009). A dynamic simulation based water resources education tool. Journal of Environmental Management 90(1), 471-482.
  3. The articles are, respectively, 1) Wise, M., et al. (2009). Implications of limiting CO2 concentrations for land use and energy. Science 324(5931), 1183-1186 and 2) Labat, D., et al. (2004). Evidence for global runoff increase related to climate warming. Advances in Water Resources 27(6), 631-642.

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