Ishay Haviv Oded Regev Amnon Ta-Shma On the Hardness of Satisfiability with Bounded Occurrences in the Polynomial-Time Hierarchy. 45-60 2007 3 Theory of Computing 1 http://dx.doi.org/10.4086/toc.2007.v003a003 db/journals/toc/toc3.html#HavivRT07