MCCARTHY, G. S. Topological Semiloops. MATHEMATICA SCANDINAVICA, [S. l.], v. 18, p. 106–112, 1966. DOI: 10.7146/math.scand.a-10785. Disponível em: https://www.mscand.dk/article/view/10785. Acesso em: 7 may. 2024.