WANBY, Göran. A generalization of the Phragmén-Lindelöf principle for elliptic differential equations. Mathematica Scandinavica, Berkeley, CA, United States, v. 43, p. 259–274, 1978. DOI: 10.7146/math.scand.a-11780. Disponível em: https://journals.msp.org/mscand/article/view/1865. Acesso em: 25 jul. 2026.