Whenever you use facts or ideas taken from others, it is essential that you give credit to the original author. Failing to do so is plagiarism, and can result in severe penalties for students (or for any scientist). See Part 4 of the Calendar for more details on the University of Lethbridge’s plagiarism policy.
Scientists give credit for borrowed ideas and information through short citations in the text of papers, combined with a detailed reference in the Literature Cited section at the end of the paper. This not only gives credit to the original author, it provides support for the arguments being presented (by showing they are based on legitimate previous research), and allows readers to find the original papers being cited and check that the information has been duplicated accurately.
Keep in mind that citations aren’t limited to direct quotes (which should be used sparingly if at all in research papers). Citations should be used whenever you use information which is not common knowledge, or derived from your own experience or imagination.
How do I cite?
Most scientific journals cite using the Name-Year system. In the text of your paper insert a short bracketed reference to the last name of the author and year of publication. For example if you are deriving information from a paper by J.D. Smith, and published in 1987, you would include (Smith 1987) in the text, as close as possible to the information being derived from Smith’s paper. If there are two authors, list both, as in (Smith and Weston 1976). Never change the order of the names from that presented in the original paper. If there are three or more authors, list only the first, followed by et al., as in (Smith et al. 1985). Et al. is written in italic font (or underlined) because it is an abbreviation of the Latin phrase “et alia” meaning “and the others.” If you have two papers by the same author(s) and from the same year, you should add letters to keep them separate, as in (Smith 1987a, Smith 1987b). Notice that several citations can be included in the same set of parentheses. You can also use your citation as the subject of the sentence. In this case, only the year is placed in parentheses. Below are a few examples of sentences containing citations.
Universal affirmatives may be only partially converted (Cleese 1971).
The arrival of the Spanish inquisition was almost always unexpected (Palin and Chapman 1972).
Instances of tri-gluteus syndrome are rare but have been documented (Cleese et al. 1973).
Jones and Palin (1975) found that African swallows could carry heavier loads than their European counterparts.
How often should I cite?
Adding a citation to every sentence can make a paper cumbersome and harder to read. When a series of ideas in a paragraph all come from the same source, it is sometimes possible to use a single citation for all. But your first priority must be to make it clear to your reader exactly what information is being cited. If in doubt, include a citation.
How do I prepare a Literature Cited section?
Your literature cited section provides detailed information on every paper cited in the text of your paper, but does not include any references not cited. It is not a bibliography of every book you consulted during your research. It only includes those from which you drew specific ideas or information.
The Literature Cited section comes at the end of your paper and is organized alphabetically by the last name of the first author. (The order of authors often ranks the role they played in the research and writing, and should never be changed.) Other information to be included is:
Initials of each author.
The year of publication.
The title of the paper (or book).
The title of the journal (for a journal article).
The volume of the journal (for a journal article).
The page numbers in the journal (for a journal article).
Publishing company (for a book).
Place of publication (for a book).
A typical Literature Cited entry for a journal article would look like this:
Beadle, G.W. and Tatum, E.L. 1942. Genetic control of a biochemical pathway in Neurospora. Proc. Natl. Acad. Sci. USA 27:499-506.
And an entry for a book would look like this:
Dawkins, R. 1989. The Selfish Gene: New Edition. Oxford University Press, Oxford.
They each provide all the information needed to go to the library, and find the article or book in question. Notice that the title of the journal is abbreviated. This is common practice, and can be frustrating for students. But you will quickly learn the abbreviations used for journals in your chosen field. Most are fairly intuitive.
What about style?
Unfortunately, there is no universal style in use for citations. Fortunately, the differences are small, and typically involve relatively minor issues such as whether all words in the title are capitalized, or whether journal titles are written in italic font. The best solution is to find a paper in the journal you are submitting your paper to, or that you have been told by an instructor to use as a template. Photocopy a few pages from Lit. Cited sections, and use them as a style guide. This can also serve as a guide to proper format for types of reference not covered here.
What about WWW sites?
No standardized format has yet been adopted for citing information available on the worldwide web. The difficulty with a web address is that it is not permanent. Once a book is published, it should be available indefinitely (although possibly difficult to locate), and the text will never change. A document published on the web may change daily, and can disappear without notice. When citing information found on the web, emphasis should be placed on author and publisher rather than simply the web address.
What about numbered citations?
A few science journals use numbered citations (formally called the Citation-Sequence system) rather than the Name-Year system described above. Here the borrowed information is identified by a number placed in the text. The first identifier in the text becomes one, the second two, and so on. Usually this number is included as a superscript at the end of a sentence, but in some journals it is placed in parentheses. The detailed information on each reference is included in a list of endnotes rather than a Lit. Cited section. The main difference is that the list is organized by number rather than alphabetically. Numbers are used as a space-saving device, but are not as easy for the reader to follow as standard citations. Use the Citation-Sequence system in a paper only if you are submitting it to a journal which requires this format, or you have been specifically asked to use this format by an instructor.