REUTOV, V. Y. Trans-Boundary Cooperation of Ukraine Regions Theoretically-practical Aspects of the Development. Przegląd Prawno-Ekonomiczny, [S. l.], n. 5 (4), p. 66–79, 2008. Disponível em: https://czasopisma.kul.pl/index.php/ppe/article/view/15223. Acesso em: 31 grudz. 2025.