GIFFEN, C. H. Link concordance implies link homotopy. MATHEMATICA SCANDINAVICA, [S. l.], v. 45, p. 243–254, 1979. DOI: 10.7146/math.scand.a-11839. Disponível em: https://www.mscand.dk/article/view/11839. Acesso em: 5 may. 2024.