Szachoń-Pszenny A. The borders of the Schengen area and the borders of the European Union - legal conditions. Bord. Reg. Stud. [Internet]. 2018 Jun. 4 [cited 2024 Nov. 2];6(1):51-75. Available from: https://czasopisma.uni.opole.pl/index.php/p/article/view/379