Reference sources include materials like encyclopedias, dictionaries, directories, or almanacs.
These sources are useful for gaining a greater general knowledge about a subject.
Reference sources contain entries/articles that have information about important people, places, dates, themes, or issues that are related to a specific topic. This information can help you generate keywords to help in your searching.
Reference sources also often have a list of references or a "Further Reading" section; these can be of great use in directing you to other useful and/or reliable resources.
The Libraries have reference sources in print and others that can be accessed online. Contact the library for help finding reference sources on your topic or subject.