AKULOV , V. F.; SHISHKOV , A. E. Uniqueness of solutions of mixed problems and the Cauchy problem for parabolic equation of high order with nonrestricted coef¬ficients. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 44, n. 2, p. 149–155, 1992. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/7826. Acesso em: 17 apr. 2025.