If you wish to refer to two or more sources at the same time, you will need to separate these out using the semicolon ';'.
Option 1: Please cite these in chronological order with the earliest date listed first.
Reference List
In-text citation
For example:
The correlation between engagement with the academic library’s support and retention should be developed to facilitate widening participation (Campbell 2017; Atkinson 2020).
Option 2: If more than one source is published in the same year, these should be cited alphabetically by author/corporate author.
Reference list
In-text citation
For example:
The correlation between engagement with the academic library’s support and retention should be developed to facilitate widening participation (Atkinson 2020; Reynolds 2020; Young 2020).