Thematic catalogs can be used to locate vocal music by a specific composer. Most of these are organized by opus or genre, and they often include an incipit (the first few bars of each movement) to help you identify the piece you're trying to find.
For more information on thematic catalogs, please see Barry Brook's Thematic Catalogue entry in Grove Music Online.
The following is a list of some of the thematic catalogs found in the Music Library. Others are located in the Music Ref ML 134 call number area and are shelved alphabetically by composer.
Some of these resources are located in the Music Library's reference section, and can only be used within the library. Click on the title to check the location and availability.