When you find one source that is helpful for your research, it often can lead to more useful sources. Strategies for finding more sources based on what you have include:
Browse the bibliography or references at the end of a relevant book or article entry in a reference work.
If you find a relevant book in the catalog, click on the title to see the full record. Then click on relevant subjects or on the author's name to see more works by them.
Use Google Scholar's "Cited by" link to find out who cited the relevant work. Or click on the author's name for other works by them.