There are two main ways of citing sources within a text:
(1) the author-page system, which is widely used in the humanities; and
(2) the author-date system, which has been adopted by the social sciences and some of the natural sciences.
Each of these systems has several variations. The recognized standard for the author-page system is The MLA Style Manual, which is published by the Modern Language Association. The most widely used version of the author-date system can be found in the Publication Manual of the American Psychological Association (APA), 3rd ed. The brief descriptions of each system that follow are based on these two sources.
The basic technique in both systems is to include just enough information in the text to enable the reader to find the relevant item in the reference list. In the author-page system, this information includes the author of the work referred to and the relevant page number.
American novelists have always had a difficult relationship with their public (Brooks 247).
If the author is mentioned in the text, then just the page number is needed in parentheses.
As Brooks has observed, American novelists have always had a difficult relationship with their public (247).
If the reference is to a work as a whole rather than to a specific part, then no additional citation is needed.
In Gilded Twilight, Brooks establishes himself as the most thoughtful of poststructuralist critics.
When there is more than one item in the reference list by the same author, the title of the work referred to is included in the parentheses, usually in a shortened form.
Brooks' comments on Melville are surprisingly negative (Gilded 83).
When works by different authors are referred to, all the references are included in the same parentheses.
Recently critics have had surprisingly negative things to say about Melville (Brooks, Gilded 83; Adams and Rubens 432; Leibniz 239).
In the author-date system, the in-text citations include the author's name and the date of publication. As with the author-page system, material that already appears in the text is not repeated within the parentheses.
A recent study carried out at McGill came to the opposite conclusion (McBain, 1991).
McBain (1991) demonstrates that there is at least one alternative to the accepted view.
In a 1991 study, McBain showed that there is at least one alternative to the accepted view.
When the reference list contains more than one work published by a particular author in the same year, letters are used to distinguish among them.
Several innovative studies in the last few years have demonstrated that this matter is not as settled as was once thought (Brewer, 1989; Fischer & Rivera, 1988; McBain, 1989a, 1989b, 1991; Silvano, Blomstedt & Meigs, 1987).
Ordinarily, page numbers are included only when there is a direct quotation.
One respected researcher notes that little notice has been taken of "the substantial number of counterexamples that have not been either questioned or explained" (McBain, 1991, p. 238).
Notice how the two systems differ in details: for example, one uses and, the other &; one follows the author's name with a comma, while the other does not.
In some publications in the sciences, the items in the reference list are numbered and these numbers are used in citations in the text.
One group of experiments has led researchers to believe that despite the enormous difficulties, a vaccine will eventually be produced (3,22,39). Much depends on the availability of funds and staff to carry out the work (14). Motley observes, however, that "whether the administration has the will to make the painful choices necessary is highly doubtful" (19, p. 687).
With a number system, the items in the reference list may be put in either alphabetical order or the order in which they occur in the text.
As mentioned above.