Cita APA

Bear, F. E., & Brown, B. E. (1949). Hunger signs in crops: A symposium. American Society of Agronomy.

Citación estilo Chicago

Bear, Firman E., and B E. Brown. Hunger Signs in Crops: A Symposium. U S A: American Society of Agronomy, 1949.

Cita MLA

Bear, Firman E., and B E. Brown. Hunger Signs in Crops: A Symposium. American Society of Agronomy, 1949.