Pepliński, B., R. Baum, and K. Wajszczuk. “Changes of the Energy Consumption of Production in Selected Farms in Wielkopolska”. Journal of Agribusiness and Rural Development, Vol. 26, no. 4, Dec. 2012, pp. 69-80, http://www1.up.poznan.pl/jard/index.php/jard/article/view/576.