Music

Huge online library of out of copyright scores.

Scores and critical commentaries of the entire Neue Mozart-Ausgabe.

"The Music Treasures Consortium provides online access to the world's most valued music manuscripts and print materials, held at the most renowned music archives, in order to further research and scholarship. Researchers can search or browse materials, access metadata about each item, and view digital images of the treasure via each custodial archive's Web site." (description from website)

A good selection of out of copyright scores from the Indiana University.

Choral sheet music can by searched by title and composer. There are also subcategories, musical eras, types of sacred music, sacred music by season, voicing, and accompaniment.