STETKAER-HANSEN, H. A Generalization of a Theorem of Wienholtz Concerning Essential Selfadjointness of Singular Elliptic Operators. MATHEMATICA SCANDINAVICA, [S. l.], v. 19, p. 108–112, 1966. DOI: 10.7146/math.scand.a-10798. Disponível em: https://www.mscand.dk/article/view/10798. Acesso em: 27 apr. 2024.