FUSHCHICH, V. I.; CHOPIK, V. I. Conditional symmetry and new representations of the Galilean algebra for nonlinear parabolic equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 45, n. 10, p. 1433–1443, 1993. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5948. Acesso em: 5 dec. 2025.