KARLSSON, P. W. Regions of Convergence for Hypergeometric Series in Three Variables. MATHEMATICA SCANDINAVICA, [S. l.], v. 34, p. 241–248, 1974. DOI: 10.7146/math.scand.a-11526. Disponível em: https://www.mscand.dk/article/view/11526. Acesso em: 7 may. 2024.