Credo's Mind Map feature provides a visual representation of your results with your search term(s) at or near the center and related hyperlinked terms radiating out.
Most reference resources are considered "tertiary" source materials. These books and websites provide background information and an overview and analysis of a subject or concept.
Tertiary sources have been compiled from secondary sources. Unlike a secondary source book or journal article, tertiary sources are not intended to be read in their entirety. Instead, they are most often used to clarify terms and concepts about a particular topic. Tertiary sources include: