BRÜDERN, J. Ternary additive problems of Waring’s type. MATHEMATICA SCANDINAVICA, [S. l.], v. 68, p. 27–45, 1991. DOI: 10.7146/math.scand.a-12343. Disponível em: https://www.mscand.dk/article/view/12343. Acesso em: 29 apr. 2024.