APA (7th ed.) Citation

Walley, J., Rinvolucri, M., & Gribben, P. (1989). Grammar games: Software pack ([Unprotected version].).

Chicago Style (17th ed.) Citation

Walley, John, Mario Rinvolucri, and Patrick Gribben. Grammar Games: Software Pack. [Unprotected version]. Cambridge, 1989.

MLA (9th ed.) Citation

Walley, John, et al. Grammar Games: Software Pack. [Unprotected version]. 1989.