Zimmer, G. F. (2000). The biological farmer: A complete guide to the sustainable & profitable biological system of farming. Austin, TX.: Acres U.S.A..
Παραπομπή Chicago StyleZimmer, Gary F. The Biological Farmer: A Complete Guide to the Sustainable & Profitable Biological System of Farming. Austin, TX.: Acres U.S.A., 2000.
Παραπομπή MLAZimmer, Gary F. The Biological Farmer: A Complete Guide to the Sustainable & Profitable Biological System of Farming. Austin, TX.: Acres U.S.A., 2000.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.