KALINOWSKI, Józef. On a boundary value problem. Annales Mathematicae Silesianae, [S. l.], v. 7, p. 73–77, 1993. Disponível em: https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14247. Acesso em: 8 may. 2025.