BESSY, Stéphane; GONÇALVES, Daniel; SERENI, Jean-Sébastien. Two-floor buildings need eight colors. Journal of Graph Algorithms and Applications, [S. l.], v. 19, n. 1, p. 1–9, 2015. DOI: 10.7155/jgaa.00344. Disponível em: https://jgaa.info/index.php/jgaa/article/view/paper344. Acesso em: 30 jun. 2024.