APA (7th ed.) Citation

Hay, R. K. M., Hay, R. K. M., & Porter, J. R. (2006). The physiology of crop yield (2nd ed.). Blackwell Publishing.

Chicago Style (17th ed.) Citation

Hay, Robert K. M., Robert K. M. Hay, and John R. Porter. The Physiology of Crop Yield. 2nd ed. Oxford ; Ames, Iowa: Blackwell Publishing, 2006.

MLA (9th ed.) Citation

Hay, Robert K. M., et al. The Physiology of Crop Yield. 2nd ed. Blackwell Publishing, 2006.