APA (7th ed.) Citation

Webber, A. L., Black, D., & Hampton, C. (1994). Sunset boulevard: Vocal selections. Really Useful Group.

Chicago Style (17th ed.) Citation

Webber, Andrew Loyd, Don Black, and Christopher Hampton. Sunset Boulevard: Vocal Selections. London: Really Useful Group, 1994.

MLA (9th ed.) Citation

Webber, Andrew Loyd, et al. Sunset Boulevard: Vocal Selections. Really Useful Group, 1994.