NEDIALKOV, E.; NENOV, N. Each 11-vertex graph without 4-cliques has a triangle-free 2-partition of vertices. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 91, p. 127–147, 1999. Disponível em: https://stipendii.uni-sofia.bg/index.php/fmi/article/view/275. Acesso em: 4 dec. 2024.