Author, A. A. (Year). Title of textbook (Edition if applicable). Publisher.
In-text citation: (Author, Year)
In-text citation with page number: (Author, Year, p. X)
For two authors: Author, A. A., & Author, B. B. (Year). Title of textbook. Publisher.
For three or more authors: Author, A. A., et al. (Year). Title of textbook. Publisher.
If the textbook has an editor instead of an author: Editor, E. E. (Ed.). (Year). Title of textbook. Publisher.
If citing a chapter in an edited textbook: Author, A. A. (Year). Title of chapter. In E. E. Editor (Ed.), Title of textbook (pp. xx–xx). Publisher.
Italicize the title of the textbook and the edition number if included.