On the Operator ⊕k,m Related to the Wave Equation and Laplacian. European Journal of Pure and Applied Mathematics, Maryland, USA, v. 14, n. 3, p. 881–894, 2021. DOI: 10.29020/nybg.ejpam.v14i3.4006. Disponível em: https://ejpam.com/index.php/ejpam/article/view/4006.. Acesso em: 21 jul. 2024.