@inproceedings{KL07,
         author      =   "O. Kupferman and Y. Lustig",
         title      =    "Lattice Automata",
         booktitle  =    "Proc. 8th International Conference on
Verification, Model Checking, and Abstract Interpretation",
         series      =   "Lecture Notes in Computer Science",
         publisher   =   "Springer-Verlag",
         year        =   "2007",
         volume      =   "4349",
         pages       =   "199 -- 213"
}