For many of the major composers such as Bach and Mozart scholars have researched and published Complete or Collected Editions of their works. For some composers this may entail more than a hundred volumes which can make it difficult to locate a particular piece of music. Fortunately there is help available through the listings in the Grove Dictionary of Music (part of Oxford Music Online) as well as the Collected editions bibliography listed below.
Thematic Catalogs are scholarly compilations that include every work by an individual composer. They generally include a few notes of the beginning of each work. the date of composition and publisher. A published bibliography of these thematic catalogs is listed below.