The number of reference works on music is voluminous. The following subject words (in the Subject Genre facet of Quicksearch) can be useful to add to your searches.

• Bibliography (a book-length guide to the literature, often with annotations)
• Chronology (a reference work organized by time period)
• Discography (a guide to recordings)
• Dictionaries (usually an encyclopedic work, in alphabetical order)
• Encyclopedias (essentially same as dictionaries)
• Indexes (a list of works and where they can be found, e.g. song indexes often name an anthology containing the song, or giving factual information about the work)