Different systems for citing references
There are many different systems for citing references. Different ones will be favoured by different disciplines eg the Harvard style is used primarily in the sciences.
Which style should I use?
Follow the recommendations of your School/Department.
If you have not been given a style to follow, Style manuals will help you decide which is appropriate for your work.
The different styles or systems of organising references and citations are often referred to by a name such as "Harvard", "Vancouver", "Chicago Manual of style", “MLA” or "name-year system". If you are referred to a particular style there are Style manuals which will give you the details of the system and format you should use. The Harvard system for citing references and compiling a bibliography is usually preferred for undergraduate level essays.
Two ways of making references in the text of your essay
In the text of your essay, references can be made either according to the Harvard system or the Number system.
- Harvard system - the name(s) of the author(s) is/are followed by the year of publication in brackets in the text. The references are then listed in the bibliography at the end of the essay in alphabetical order of the first author’s surname.
- Number system - a number is allocated to each reference and this is inserted in the text as a superscript number or in parentheses eg (3). In the bibliography at the end, the references are listed in the order in which they are cited in the text.
The following examples show the difference between the two systems.
Harvard system
Text
In the text of the paper the name(s) of the author(s) is/are followed by the year of publication in brackets. For example:
"Recently, Li and Raichlen (1999) have found a nonlinear correction to Synolakis's formula. For the three-dimensional case, Carrier and Noiseux (1983) have analysed the reduction of a tsunami wave theory."
References
In the bibliography or list of references the authors are listed in alphabetical order by the first author's surname. For example:
Carrier, G.F. and Noiseux, C.F. (1983). The reflection of obliquely incident tsunamis. J. Fluid Mech. 133, 147-160.
Li, Y. and Raichlen, F. (1999). Solitary wave run-up on plan slopes. Research report, W.M. Keck Laboratory of Hydraulics, and Water Resources, California Institute of Technology, Pasadena.
Ways of referring to one or more authors in the text
The ways in which you may refer to one or more authors in your text is shown in the examples below:
One author: Carrier (1983) or (Carrier, 1983)
Two authors: Carrier and Noiseux (1983) or (Carrier and Noiseux, 1983)
Three or more: Carrier et al. (1998) or (Carrier et al., 1998)
Ways of referring to multiple references by the same author
If there is more than one reference in your essay by the same author then these should be listed chronologically, eg:
Carrier (1966)
Carrier (1970)
Number system
Text
In the text - a number is allocated to each reference and this is inserted in the text as a superscript number or in parentheses. For example:
"Double flowers are being sought by one breeder (10), but others consider the single flower more beautiful. The hybrid clone 'Annie J. Hemming' (11) frequently produces six or seven petals rather than the five typical of the genus Hibiscus."
If a reference is cited more than once, the same number is used.
References
In the bibliography or list of references the references are usually listed in number order. For example:
10. Kennedy, C.S. (1960). Adventures with hardy herbaceous Hibiscus. Amer. Hort. Mag. 39 (4): 199-203.
11. Hemming, E.S. (1952). The perfect Mallow (Hibiscus) Marvel. Plant Life. 8: 153-154.
See the section above for help with references written by more than one author.
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