If you are citing multiple sources in the same reference, you should list them in alphabetical order, to reflect the order within the reference list, separated by a semi-colon.
(Adam et al. 2018; Carpenter et al. 2015; Zepke 2017)
If you want to give emphasis to some authors over other authors, separate the sources so that the emphasised source(s) appear first and the remainder follow the words ‘see also’.
(Giddens 1991; see also Archer 2003, 2007)
If you are citing multiple works by the same author published in different years at the same point in your text, you should list the author’s last name followed by the relevant years of publication.
(Archer 2003, 2007, 2012)
When citing information from multiple pages within the same source, you should cite consecutive pages (i.e., two or more pages in a row) with pp. followed by the page number range.
Zepke (2017, pp. 55–56)
For information from non-consecutive pages list each page number separated by a comma.
Zepke (2017, pp. 14, 55, 102)
NB: a quote over consecutive pages will require a page range, however, this is rarely likely for a paraphrase.