APA (7th ed.) Citation

Beels, C., Hopson, B., & Scally, M. (1992). assertiveness: A positive process. Mercury Books.

Chicago Style (17th ed.) Citation

Beels, Christine, Barrie Hopson, and Mike Scally. Assertiveness: A Positive Process. London: Mercury Books, 1992.

MLA (9th ed.) Citation

Beels, Christine, et al. Assertiveness: A Positive Process. Mercury Books, 1992.