Option 1: scan the reference list/bibliography of articles/books you already have to find citations of articles of interest to you.
Option 2: search for the articles/books you already have in Google Scholar to see what journal articles have cited them.
Option 3: search for the articles/books you already have in Web of Science to see what journal articles have cited them.
The following databases at UVic have good coverage of peer-reviewed scholarly journal articles in the subject area.
Databases/Journals outside UVic: