Ostromęcki, Artur, Andrzej Mantaj, and Dariusz Zając. 2015. “THE IMPORTANCE OF NON-AGRICULTURAL ECONOMIC ACTIVITY OF FARMERS IN THE MODERNIZATION PROCESS OF FARMS”. Acta Scientiarum Polonorum. Oeconomia 14 (4):83-92. https://aspe.sggw.edu.pl/article/view/418.