BULITKO, V. V.; BULITKO, V. K. On a criterion of $NP$-completeness. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 50, n. 12, p. 1686–1691, 1998. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4788. Acesso em: 6 dec. 2025.