Cita APA (7th ed.)

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

Cita Chicago (17th ed.)

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

Cita MLA (9th ed.)

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