FLEISCHNER, H. J.; GELLER, D. P.; HARARY, F. Outerplanar Graphs and Weak Duals. The Journal of the Indian Mathematical Society, [S. l.], v. 38, n. 1-4, p. 215–219, 1974. Disponível em: https://www.informaticsjournals.com/index.php/jims/article/view/16694. Acesso em: 20 apr. 2024.