Chicago or Turabian citation style
The Chicago or Turabian style is sometimes called the documentary note or humanities style. The Chicago Manual of Style, 17th ed. (2017) and Turabian's A Manual for Writers of Research Papers, Theses, and Dissertations, 9th ed. (2018) give examples of both the humanities and author-date citation styles.
Also see the University of Wisconsin-Madison Chicago/Turabian Documentation Style page.