BALIBREA, Francisco; CÁNOVAS PEÑA, Jose S.; LÓPEZ, Víctor Jiménez. Some invariants for σ-permutation maps. Annales Mathematicae Silesianae, [S. l.], v. 13, p. 51–60, 1999. Disponível em: https://trrest.vot.pl/ojsus/index.php/AMSIL/article/view/14136. Acesso em: 7 may. 2025.