Szmidt, Katarzyna, Armand Kasztelan, Maria Kierepka, and Andrzej Samborski. 2016. “DIVERSIFICATION IN THE INCOME LEVELS OF EU FARM HOLDINGS SPECIALIZING IN THE PRODUCTION OF MILK”. Acta Scientiarum Polonorum. Oeconomia 15 (1), 133-43. https://js.wne.sggw.pl/index.php/aspe/article/view/4218.