The Harvard Dictionary of Music by 
Music Reference and Research Materials: An Annotated Bibliography by 
The New Grove Dictionary of Music and Musicians by 
World Music: Latin & North America, Caribbean, India, Asia and Pacific by An alternative to Wikipedia. Reference works such as encyclopedias are a good place to find background information on a topic, or to quickly look up a fact. They often include bibliographies telling you where to find additional information.
Credo Reference provides access to a broad variety of reference sources from dictionaries to encyclopedias covering topics from the arts to the sciences. It has an image collection, maps, customizable data, and audio pronunciation files. You can search the whole collection or a specific subject area.
