VALQUI HAASE, Christian Holger. Árboles binarios, álgebra tensorial no asociativa y una c-álgebra universal. Pro Mathematica, [S. l.], v. 13, n. 25-26, p. 17–30, 1999. Disponível em: https://revistas.pucp.edu.pe/index.php/promathematica/article/view/8147. Acesso em: 12 dic. 2025.