LIGĘZA, Jan. Existence of positive solutions of some integral equations. Annales Mathematicae Silesianae, [S. l.], v. 18, p. 21–38, 2004. Disponível em: https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14089. Acesso em: 7 may. 2025.