MCCARTHY, G. S. Topological Semiloops. Mathematica Scandinavica, Berkeley, CA, United States, v. 18, p. 106–112, 1966. DOI: 10.7146/math.scand.a-10785. Disponível em: https://journals.msp.org/mscand/article/view/2512. Acesso em: 25 jul. 2026.