MLA

Thomson, Virgil, 1896-1989. [Chamber music] Chamber music / music by Virgil Thomson ; words by Alfred Kreymborg.. Box 29A/39, folder 396. 1804-1990 (inclusive). https://collections.library.yale.edu/catalog/32295089.

APA, 6th edition

Thomson, Virgil, 1896-1989. (["Box 29A/39, folder 396"])(1804-1990 (inclusive))[[Chamber music] Chamber music / music by Virgil Thomson ; words by Alfred Kreymborg.]. https://collections.library.yale.edu/catalog/32295089.