?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.aufirst=Stefan&rft.au=Edelkamp%2C+Stefan&rft.aulast=Edelkamp&rft.date=2004&rft.title=Abstraction+in+directed+model+checking&rft.genre=proceeding