Unlike books and articles, which are narrow in focus, Tertiary or Reference sources are broad works meant to get you started by providing overview and pointing you to useful primary and secondary sources. These include:
Note: These are usually scholarly sources but not considered peer reviewed; use an encyclopedia article to identify other useful sources, but know it doesn't count as a peer reviewed article.
Though many of our print encyclopedias have been replaced with digital editions, we still have quite a few volumes in the main library. Start in the call number D section.