КЛЮС, І. Multipoint problem for differential equations with partial derivatives with variable coefficients. Proceedings of National Aviation University (archive), [S. l.], v. 30, n. 4, p. 209–211, 2006. DOI: 10.18372/2306-1472.30.1422. Disponível em: http://jrnl.kai.edu.ua/index.php/visnik/article/view/1422. Acesso em: 16 apr. 2026.