KHADZHIIVANOV, N.; NENOV, N. BALANCED VERTEX SETS IN GRAPHS. Ann. Sofia Univ. Fac. Math. and Inf., [S. l.], v. 97, p. 81–95, 2005. Disponível em: https://annual.uni-sofia.bg/index.php/fmi/article/view/145. Acesso em: 9 apr. 2025.