APA

Oelhaf R. C., . (1978). Organic agriculture : economic and ecological comparisons with conventional methods. New York: John Wiley & Sons.

Chicago

Oelhaf Robert C, . 1978. Organic agriculture : economic and ecological comparisons with conventional methods. New York: John Wiley & Sons.

Harvard

Oelhaf R. C., . (1978). Organic agriculture : economic and ecological comparisons with conventional methods. New York: John Wiley & Sons.

MLA

Oelhaf Robert C, . Organic agriculture : economic and ecological comparisons with conventional methods. New York: John Wiley & Sons. 1978.