@inproceedings{KV01b, author = "O. Kupferman and M.Y. Vardi", title = "On clopen specifications", booktitle = "Proc. 8th International Conference on Logic for Programming, Artificial Intelligence and Reasoning", series = "Lecture Notes in Computer Science", volume = "?", pages = "?", publisher = "Springer-Verlag", year = "2001", }