APA (7th ed.) Citation

Clark, M. J., Gregory, K. J., & Gurnell, A. M. (1987). Horizons in physical geography. Barnes & Noble.

Chicago Style (17th ed.) Citation

Clark, M. J., K. J. Gregory, and A. M. Gurnell. Horizons in Physical Geography. Totowa, NJ: Barnes & Noble, 1987.

MLA (9th ed.) Citation

Clark, M. J., et al. Horizons in Physical Geography. Barnes & Noble, 1987.