Czyżewski, A., and J. Staniszewski. “LAND AND LABOUR PRODUCTIVITY IN POLISH AGRICULTURE AGAINST HIGHLY-DEVELOPED COUNTRIES OF THE EUROPEAN UNION”. Acta Scientiarum Polonorum. Oeconomia, Vol. 15, no. 4, Dec. 2016, pp. 53-63, https://js.wne.sggw.pl/index.php/aspe/article/view/4254.