Sometimes an author of a book, article, or website will mention another person’s work by using a quotation or paraphrased idea from that source. (This may be called a secondary source.) For example, let's say you are reading a Kirkey article that includes a quotation by Smith that you would like to include in your essay.
Examples of in-text citations:
According to a study by Smith (qtd. in Kirkey) 42% of doctors would refuse to perform legal euthanasia.
Smith (qtd. in Kirkey) states that “even if euthanasia was legal, 42% of doctors would be against this method of assisted dying” (A.10).
Example of Reference list citation:
Kirkey, Susan. "Euthanasia." The Montreal Gazette, 9 Feb. 2013, p. A.10. Canadian Newsstand Major Dailies.