Sanjeev Khanna Aravind Srinivasan Special issue: 35th Annual ACM Symposium on Theory of Computing. 305- 2004 69 J. Comput. Syst. Sci. 3 http://dx.doi.org/10.1016/j.jcss.2004.06.004 db/journals/jcss/jcss69.html#KhannaS04