The Chicago style, when referring to a source of information within the text of a document, in its simplest form, gives a short citation consisting of the name of the author (or authors) and the date of publication:
• The short references within the text are given wholly or partly in round brackets.
• Use only the surname of the author followed by the year of publication. Include page, chapter, section or paragraph numbers if you need to be specific. A comma is placed between the year of publication and the page, chapter, section or paragraph numbers.
• No distinction is made between books, journal articles, internet documents or other formats except for electronic documents that do not provide page numbers. In this instance, use the paragraph number, if available, with the abbreviation par.
• Citations in the text can either be either placed at the end of a sentence in parentheses (brackets) or alternatively, the author's name may be included in the text, and just the date and additional information placed within the brackets.
• A citation for a book appearing in the text as:
There are many reasons for intestinal scarring (Ogilvie 1998, 26-28).
would be found in the reference list in the following form:
Ogilvie, Timothy H. 1998. Large Animal Internal Medicine. Baltimore, MD: Williams and Wilkins.
• A citation for a journal article appearing in the text as either:
... gastrointestinal illness is also often misdiagnosed (Morgan and Thompson 1998, 243).
Morgan and Thompson (1998, 243) argue that gastrointestinal illness is also often misdiagnosed.
would be referenced as:
Morgan, U. M., and R.C. A. Thompson. 1998. "PCR Detection of Cryptosporidium: The Way Forward." Parasitology Today 14, no. 6 (December): 241-245.
• An electronic document would be cited in the text in the same way as a print document.
For example, citation for an internet document appearing in the text as:
There are many useful materials available (Raidal and Dunsmore 1996, par. 13)
would be given in the reference list as:
Raidal, Shane R., and Jon Dunsmore. 1996. Parasites of Companion Birds: A Survey of Alimentary Tract Parasites in Caged Psittacine Birds with Specific Reference to the Prevalence of Trichomonas Gallinae. http://wwwvet.murdoch.edu.au/caf/parasit.htm.
Note: When referring to multiple authors within the text and within parentheses, precede the final name with the word and
... as Kurtines and Szapocnik (2003) demonstrated.
... as has been demonstrated (Kurtines and Szapocnik, 2003).