APA (7th ed.) Citation

Percil, J., & Gray, J. (1988). Prospects: An advanced course teacher's book. Penguin Books.

Chicago Style (17th ed.) Citation

Percil, John, and Joanna Gray. Prospects: An Advanced Course Teacher's Book. London: Penguin Books, 1988.

MLA (9th ed.) Citation

Percil, John, and Joanna Gray. Prospects: An Advanced Course Teacher's Book. Penguin Books, 1988.