BIGUN, Ya. I. Existence, uniqueness, and dependence on a parameter of solutions of differential-functional equations with ordinary and partial derivatives. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 5, p. 715–719, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5053. Acesso em: 5 dec. 2025.