STANĚK, Svatoslav. Boundary value problems for one-parameter second-order differential equations. Annales Mathematicae Silesianae, [S. l.], v. 7, p. 89–98, 1993. Disponível em: https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14249. Acesso em: 1 jul. 2025.