Citation, Documentation of Sources
Q. If you quote a sentence that includes an APA-style reference in parentheses, do you quote it with the reference, or would you cut it out?
A. Unlike a superscript note reference number in the text, which is meaningless without the text of the note, an APA-style text reference—for example, “(Smith, 2020)” in APA or “(Smith 2020)” in Chicago’s similar author-date style—includes at least some substantive information. So keep the parenthetical reference in your quoted text. Readers may not be able to decipher the reference without tracking down the original (with the help of your own source citation), but they’ll have an easier time locating the quoted text if you leave it intact. For more details, see CMOS 13.7, item 5.