Nasalski, Z., B. Rychlik, and T. Sadowski. “EFFICIENCY OF CHANGEOF PLANTS CULTIVATION FROM CONVENTIONAL TO ECOLOGICAL AGRICULTURE SYSTEM”. Acta Scientiarum Polonorum. Oeconomia, Vol. 7, no. 3, Sept. 2008, pp. 67-79, https://js.wne.sggw.pl/index.php/aspe/article/view/3788.