The Library of Congress' M classification numbers are used for collections of music by various composers (M1, M2, M5-) and for editions of a composer's complete works (M3). Within these numbers/classifications, the music is arranged further by the medium of the performance (i.e. instrumental or vocal works). Instrumental works - M5 - M1450, and vocal works - M1495 - 2199.
Musical dictionaries, encyclopedias, bibliographies (especially of repertoire), and bio-bibliographies
Start with a keyword search.
In the Quick Search box, type in the composer and title.
If you have incomplete information, use the New Grove Dictionary of Music and Musicians accessible from Oxford Music to locate more.
Keyword searching: composer or performer, title, publisher, or instrument
Subject searching: try searching by type of music (jazz, folk, chamber, etc.), type of musician (singers, composers, etc.), geographic region, or time period.
Use the facets (limiters/filters) on the search results page to narrow your search.
Search by the preferred title.
Preferred titles (formerly called Uniform Titles) - a preferred title is used to link editions of the same work. This is helpful since music exists in many formats and is published in multiple languages.
Facets
Facets help to narrow a search. For example, use the facet for Material Type and select Score, if you are looking for sheet music.
Other helpful facets for music scholars include the Language facet and Author/Creator facet.
In the image above, I searched Quick Search using the name of the composer and a keyword from the title. I then used the facets on the left hand side of the results page to limit by Material Type. In this case, I selected Scores.
Scores ("M"):
Mini-scores - for study purposes
Full scores - for study or conducting
Scores & parts - for chamber music
Piano reductions - of ballets, symphonies
Piano-vocal scores - reductions of operas, oratorios, cantatas
Vocal scores - for solo voice or voice with piano accompaniment