APA (7th ed.) Citation

Hay, R. K. M., & Walker, A. J. (1989). An introduction to the physiology of crop yield. Longman Scientific & Technical.

Chicago Style (17th ed.) Citation

Hay, Robert K. M., and Andrew J. Walker. An Introduction to the Physiology of Crop Yield. New York: Longman Scientific & Technical, 1989.

MLA (8th ed.) Citation

Hay, Robert K. M., and Andrew J. Walker. An Introduction to the Physiology of Crop Yield. Longman Scientific & Technical, 1989.