Q. In the author-date format, are multiple references divided by commas or semicolons?
A. Use semicolons to separate references by different authors. If there are also locators, put a comma between the year and locator. Multiple references to works by the same author are separated by a comma unless a page number intervenes (as in the example citing Wong below).
(Armstrong and Malacinski 1989; Beigl 1989; Pickett and White 1985)
(Wong 1999, 328; 2000, 475; García 1998, 67)
(Schonen et al. 2023, 2024)