ETESSAMI, K.; VARDI, M. Y.; WILKE, T. First-Order Logic with Two Variables and Unary Temporal Logic. BRICS Report Series, [S. l.], v. 4, n. 5, 1997. DOI: 10.7146/brics.v4i5.18784. Disponível em: https://tidsskrift.dk/brics/article/view/18784. Acesso em: 26 apr. 2024.