Powęska, H. “THE SHARE OF CROSS-BORDER SHOPPING IN POLAND'S TRADE TURNOVER OF FOOD PRODUCTS WITH THE NEIGHBOURING COUNTRIES ON THE EU'S EXTERNAL BORDER”. Acta Scientiarum Polonorum. Oeconomia, Vol. 13, no. 4, Dec. 2014, pp. 147-55, https://js.wne.sggw.pl/index.php/aspe/article/view/4150.