This document discusses six common types of reference materials: dictionaries, thesaurus, encyclopedia, atlas, almanac, and periodicals. It provides examples and brief descriptions of each type of reference material, including what kind of information can be found in them and how they are used. Some key points covered include how dictionaries are used to look up words, a thesaurus is used to find synonyms and antonyms, an encyclopedia provides more detailed information about topics, and an atlas contains maps.