APA (7th ed.) Citation

Simmonds, N. W. (1979). Principles of crop improvement. Longman.

Chicago Style (17th ed.) Citation

Simmonds, N. W. Principles of Crop Improvement. London ; New York: Longman, 1979.

MLA (9th ed.) Citation

Simmonds, N. W. Principles of Crop Improvement. Longman, 1979.