A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Information required in citations
General introduction to citation practices
Part II. Source Citation

Over the long tradition of citing sources, as researchers in different fields began to write in different ways, they also developed distinctive ways of citing and documenting their sources. When citation methods became standardized, researchers had to choose from not just one or two standards but many.

Citation styles differ in the elements included and in the format of these elements, but they have the same aim: to give readers the information they need to identify and find a source. For most sources, including books, articles, unpublished documents, online sources, and other written material, that information must answer these questions:

Who wrote, edited, or translated the text (sometimes all three)?

What data identify the text? This includes the title and subtitle of the work; title of the journal, collection, or series it appears in, as well as volume number, edition number, or other identifying information; and page numbers, URL, or other locating information if the reference is to a specific part of a larger text.

Who published the text, and when? This includes the name of the publisher and the place and date of publication—or an indication that the document has not been published.

Details vary for other sources, such as sound and video recordings, but they answer the same three questions: Who wrote, edited, translated, or assembled the source? What data identify it? Who published it and when?

Your readers will expect you to use the citation style appropriate to their particular field, not just because they are familiar with this style but because when you use it, you show them that you understand their values and practices. The details, however, are complex: when to use capitals, periods, commas, even where to put a space. But if you do not get these small matters right, many of your readers will question whether they can trust you on the bigger ones. Few researchers try to memorize all these details. Instead, they learn the form of the citations they use most so that they do not need to look them up repeatedly. Then, for citing sources that are less common or have unusual elements, they consult a book like this one.