WANBY, G. A generalization of the Phragmén-Lindelöf principle for elliptic differential equations. MATHEMATICA SCANDINAVICA, [S. l.], v. 43, p. 259–274, 1978. DOI: 10.7146/math.scand.a-11780. Disponível em: https://www.mscand.dk/article/view/11780. Acesso em: 2 may. 2024.