MARSTRANDER, Otto. On a problem of Frobenius. Mathematica Scandinavica, Berkeley, CA, United States, v. 58, p. 161–175, 1986. DOI: 10.7146/math.scand.a-12138. Disponível em: https://journals.msp.org/mscand/article/view/1491. Acesso em: 25 jul. 2026.