APA (7th ed.) Citation

Baron, L., Kayden, M., Marier, T., & Morgan, J. (1957). Gregorian chant. Smithsonian Folkways.

Chicago Style (17th ed.) Citation

Baron, Ludovic, Mildred Kayden, Theodore Marier, and Josephine Morgan. Gregorian Chant. [Washington, D.C.]: Smithsonian Folkways, 1957.

MLA (9th ed.) Citation

Baron, Ludovic, et al. Gregorian Chant. Smithsonian Folkways, 1957.