Παραπομπή APA

Oelhaf, R. C. (1978). Organic agriculture: Economic and ecological comparison with conventional methods. alleheld Osmun ands Co Publishers.

Παραπομπή Chicago Style

Oelhaf, R C. Organic Agriculture: Economic and Ecological Comparison with Conventional Methods. New Jersey: alleheld Osmun ands Co Publishers, 1978.

Παραπομπή MLA

Oelhaf, R C. Organic Agriculture: Economic and Ecological Comparison with Conventional Methods. alleheld Osmun ands Co Publishers, 1978.