SHOCK, Robert. On orders in rQF-2 rings. Mathematica Scandinavica, Berkeley, CA, United States, v. 38, p. 192–198, 1976. DOI: 10.7146/math.scand.a-11628. Disponível em: https://journals.msp.org/mscand/article/view/2021. Acesso em: 25 jul. 2026.