@article {LutMayCVKL, title = {Cook versus Karp Levin Separating Completeness Notions If NP Is Not Small}, journal = {Theoretical Computer Science}, volume = {164}, year = {1996}, pages = {141-163}, url = {http://webdiis.unizar.es/\%7Eelvira/publicaciones/cvkl.ps.gz}, author = {J.H. Lutz and E. Mayordomo} }