Reference sources may contain citations to other publications. Look under the Reference Sources tab. Identify the useful titles, then search for them in the UTL catalogue.
Bibliographies in scholarly books often list additional sources consulted on a topic. Look at the list of references in reserve material for your course and assigned course readings
Footnotes in books and journal articles refer to the sources used by the author to support the discussion in the publication. Search for them in the UTL catalogue.