GORBACHUK, V. M. On the uniqueness of solutions of the Dirichlet and Neumann problems for an elliptic second-order differential equation on a semiaxis. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 11, p. 1564–1567, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5596. Acesso em: 5 dec. 2025.