Rodney G. Downey, Michael R. Fellows, Kenneth W. Regan. W hierarchy. In Paul Beam, Samuel R. Buss, editors, Proof Complexity and Feasible Arithmetics, Proceedings of a DIMACS Workshop, New Brunswick, New Jersey, USA, April 21-24, 1996. Volume 39 of DIMACS Series in Discrete Mathematics and Theoretical Computer Science, pages 119-134, DIMACS/AMS, 1996.
Abstract is missing.