Place this at the relevant point in the sentence or at the end of the sentence, putting the author’s name, publication date separated by a semi-colon

Where several publications from a number of authors are referenced, the references should be cited in chronological order (i.e. earliest first): Studies from the 1950s (Donovan, 1956; Peterson, 1958) demonstrated the…… More recently, researchers (Milestone, 1999; Russel, 2000; Samba, 2018) claim that..