MEL'NICHENKO, I. P. Algebras of Functionally Invariant Solutions of the Three-Dimensional Laplace Equation. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 55, n. 9, p. 1284–1290, 2003. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4002. Acesso em: 6 dec. 2025.