CHMIELEWSKI, Tadeusz J. The Future of the National Ecological System in Poland. Problemy Ekorozwoju, [S. l.], v. 4, n. 2, p. 73–82, 2009. Disponível em: https://ph.pollub.pl/index.php/preko/article/view/4693. Acesso em: 17 apr. 2025.