Location is a required part of an end reference. It indicates the specific point within a work at which the information be referenced is located. The location can be pages in a journal, pages in a book chapter, or a descriptive location in an electronic publication.
Extent, the total physical size of a work, is optional.
Books
If you are citing an entire book, location or pagination is optional (29.3.7.2.7).
Location for part of a book or monograph consists of the beginning and concluding pages of the chapter or part.
Place location information after the publisher name followed by a period as, "p. 456-463." or "Figure 1.3, Mitochondria formations.".
Examples:
Shakelford RT. 1978. Surgery of the alimentary tract. Philadelphia (PA): W.B. Saunders. Chapter 2, Esophagoscopy; p. 29-40.
Hazeltine WA. (1990). AIDS. In: The encyclopedia Americana. International ed. Danbury (CT): Grolier Incorporated. p. 365-366.
Journal articles (29.3.6.9.1)
Entire article:
Location consists of the first and last page of the article.
Retain page numbers as they appear in the publication, as XI, v-vii, N37-N49, 230s-252s.
Place location information after the volume/issue preceded by a colon.
Part of an article:
Location consists of the name or title of the part and its pagination.
Capitalize only the first word of the part title, as in other titles. Separate the numeration with a comma and space; separate the title and pagination with a semicolon and space.
Place the part location after the location information for the article itself, separated by a period.
Example:
Brown JT, Merriweather A. 2007. Immunochemistry. J Chem. 9(3 Suppl.):78S-85S. Table 2, Cost study; p. 83.
Newspapers
Location/pagination differs in newspaper articles. Give only the first page of the article followed by the column number in which the article begins. Enclose the column information in parenthesis followed by a period.
An article located in Section 1, page 42, column 4 would be given as: Sect. 1:42 (col.4).