quartets include The Oak Ridge Boys; The Statler Brothers; The Ames Brothers; The Chi-Lites; Crosby, Stills, Nash & Young; The Dixie Hummingbirds; The Four Aces; The Four Freshmen; The Four Seasons; Four Tops; The Statesmen Quartet; The Blackwood Brothers; Cathedral Quartet; Ernie Haase & Signature Sound; Golden Gate Quartet; The Hilltoppers; The Jordanaires; and The Mills Brothers. The only known U.S. drag quartet is The Kinsey Sicks. Some mixed-gender vocal quartets include The Pied Pipers; The Mamas & the Papas; The Merry Macs; and The Weavers. Folk music Russian A Russian folk-instrument quartet commonly consists of a bayan, a prima balalaika, a prima or alto domra, and a contrabass balalaika (e.g., Quartet Moskovskaya Balalaika). Configurations without a bayan include a prima domra, a prima balalaika, an alto domra, and a bass balalaika (Quartet Skaz); or two prima domras, a prima balalaika, and a bass balalaika. References Further reading Allen, Ray. Singing in the Spirit: African-American Sacred Quartets in New York City, in series, Publication[s] of the American Folklore Society: New Series. Philadelphia, Penn.: University of Pennsylvania Press, 1991. xx,[2], 268 p., ill. with b&w photos. pbk. Chamber music Types of musical groups Four-part harmony