Background sources like encyclopedias can provide context for your topic, or even help you choose one. They are great places to start because:
What is a reference work?
A book (such as a dictionary, encyclopedia, handbook, etc.) intended primarily for consultation rather than for consecutive reading. Usually, these contain short, fact-driven entries.
How do you find reference works?
Perform a simple BANC search using your keywords and then limit to "Reference Collection"
- OR -
Use a database of reference books, such as Gale Virtual Reference, linked to below