Librettos are usually filed under the COMPOSER, even though the librettist may be a different person.
Call number examples follow. Use these to aid your understanding of how the librettos are organized.
Hotlinks in blue.
Miscellaneous collections : ML 47
Example : ML 47 .F46 L86 2003
This is a compilation of three musical works by three different composers/authors.
Collections by two or more composers (or authors) : ML 48
Example : ML 48 .R5 vol.1 and 2
This is a compilation of the librettos for American musicals by two or more composers.
Collections by one composer (or author) : ML 49
Example : ML 49 .S67 F68 2000
This is a compilation of librettos for four musicals by Stephen Sondheim.
Separate works : ML 50
Example : ML 50 .S705 A59 1976
This is one libretto, for Anyone can whistle, composer Stephen Sondheim.