Research Guides: Classical Period Music (ca. 1750-1800 + Beethoven): A Guide to Research and Resources: Composers & Publishers

Databases

Beethoven Bibliography Database
A fully-indexed bibliography of published (and selected unpublished) materials relating to Ludwig van Beethoven maintained by the American Beethoven Society.

Oxford Online Bibliographies compile authoritatively selected and annotated citations for key reference works, collected correspondence, biographies, monographs, and articles relating to prominent composers.
Research guides provide detailed listings for a composer's known musical and literary works followed by annotated bibliographies of the secondary literature on the composer's œuvre arranged by genre and important topics in the composer's life, career, and reception history—plus other features such as a genealogies, chronologies, and indexes.
Companions collate major essays by established experts that address key aspects of the composer's career, creative work, style, and critical reception.

Christoph Willibald Gluck: A Guide to Research (Online) by Patricia Howard
Call Number: Reference (SV) ML 134 .G56 H7 2003 (print version)
Publication Date: 2003
The Cambridge Companion to Haydn (Online) by Caryl Clark (editor)
Call Number: Reference (SV) ML410.H4 C17 2005 (print version)
Publication Date: 2005
Chapters on Haydn and his contemporaries, his working environments in Eisenstadt and Eszterháza, the reception of his music, and a survey of the major genres in which Haydn wrote.
The Cambridge Companion to Mozart (Online) by Simon P. Keefe (editor)
Call Number: Reference (SV) ML410.M9 C255 2003 (print version)
Publication Date: 2003
Comprehensive coverage of all of his important works, the reception of his music since his death, and the contexts which inform his work and his significance as a performer.