@inproceedings{KS06,
    author    =    "O. Kupferman and S. Sheinvald-Faragy",
    title     =    "Finding Shortest Witnesses to the Nonemptiness of 
                    Automata on Infinite Words",
    booktitle =    "Proc. 17th International Conference on Concurrency Theory",
    pages           = "492--508",
    series    = "Lecture Notes in Computer Science",
    volume    = 4137,
    publisher = "Springer-Verlag",
    year      = 2006
}