Musical America Directory - An annual publication that includes contact information for more than 14,000 performers and performing arts organizations, scholarship and festival listings, and more. There is also an online version available for institutional and individual subscription.
Thematic Catalogs - A thematic catalog lists the entire repertoire of an individual composer. They may be organized chronologically or by genre. Each entry includes a musicial incipit of the opening bars of the work (including individual movements within a larger work), making thematic catalogs an excellent resource for identifying details about a mystery work. The Bach-Werke-Verzeichnis by Wolfgang Schmieder is a good example of the genre.
Discographies - Discographies are bibliographies of sound recordings. They are particularly useful for locating recordings of global music and jazz. The Penguin Guide to Jazz is a good example of the genre.