PRÁSTARO, A.; RASSIAS, T. M. Results on the J. d’Alembert equation. Annales Universitatis Paedagogicae Cracoviensis Studia Mathematica, [S. l.], v. 1, p. 117–128, 2001. Disponível em: https://studmath.uken.krakow.pl/article/view/13522. Acesso em: 30 oct. 2026.