DIEU, N. Q.; LONG, T. V. Product property of global $P$-extremal functions. MATHEMATICA SCANDINAVICA, [S. l.], v. 127, n. 3, 2021. DOI: 10.7146/math.scand.a-129007. Disponível em: https://www.mscand.dk/article/view/129007. Acesso em: 22 jan. 2022.