@inproceedings{SV03CSL,
    author = {Samer, Marko and Veith, Helmut},
    title = {Validity of {CTL} Queries Revisited},
    booktitle = {Proceedings of the 12th Annual Conference of the European Association for Computer Science Logic (CSL'03)},
    editor = {Baaz, Matthias and Makowsky, Johann A.},
    publisher = {Springer-Verlag},
    series = {Lecture Notes in Computer Science},
    volume = {2803},
    pages = {470--483},
    year = {2003},
    isbn = {978-3-540-40801-7}
}