STANĚK, Svatoslav. On the existence of two solutions of functional boundary value problems. Annales Mathematicae Silesianae, [S. l.], v. 14, p. 93–109, 2022. Disponível em: https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14131. Acesso em: 2 jul. 2025.