What are reference sources?
Reference sources are works that help you locate information about people, facts, and ideas. These sources can help you find the date of an important event, major achievements of an individual or organization, or a definition of a term or concept. They are sometimes called tertiary sources. In order to find good secondary sources, it's often helpful to consult reference materials.
Examples include:
Dictionaries/encyclopedias (may also be secondary), almanacs, fact books, Wikipedia, bibliographies (may also be secondary), directories, guidebooks, manuals, handbooks, and textbooks (may be secondary), indexing and abstracting sources.
What is a biography?
Biographical entries in encyclopedias are one example of a tertiary source. You can find such entries on the open web, in library databases, and in print encyclopedias. You can also find book-length biographies in the library catalog. Here are some places you can search for biographical encyclopedia entries: