Expand upon your Reference research with Monographs.
These full-length books - also called Secondary Source books - will have more specific information about your topic.
Sometimes there's a whole book on your topic, and sometimes a chapter or section.
Monographs are written by scholars and subject experts.
The author often presents a new interpretation of a topic based upon a synthesis of primary sources, secondary source books, journal articles, and other scholarly materials.
Monographs contain a bibliography of sources or notes citing sources used or recommended by the author.