HOARE, A. H. M. Nielsen methods in groups with a length function. MATHEMATICA SCANDINAVICA, [S. l.], v. 48, p. 153–164, 1981. DOI: 10.7146/math.scand.a-11908. Disponível em: https://www.mscand.dk/article/view/11908. Acesso em: 5 may. 2024.