APA
BLACK C. A., . (1971). Agronomy in a changing world and research needs for the seventies. America: American Society for Agronomy.
Chicago
BLACK C A, . 1971. Agronomy in a changing world and research needs for the seventies. America: American Society for Agronomy.
Harvard
BLACK C. A., . (1971). Agronomy in a changing world and research needs for the seventies. America: American Society for Agronomy.
MLA
BLACK C A, . Agronomy in a changing world and research needs for the seventies. America: American Society for Agronomy. 1971.