Reference sources include books like dictionaries and encyclopedias which contain relatively brief entries on a wide variety of topics. There are a number of reference works that cover the people, institutions, and ideas that make up the history of dance. Reference sources are a great place to start your research, and many of them are available online.
Music research gateway that includes Grove Music, Oxford Dictionary of Music, Oxford Companion to Music. Authoritative online music dictionary/encyclopedia. Articles include biographies of composers and performers; definitions of terms, styles, and concepts; essays on world music, popular music, and jazz; descriptions of musical instruments and their makers, etc. Gives music examples and links to related web sites (some of which display images and play sounds).