Piotr Berman Marek Karpinski Improved Approximation Lower Bounds on Small Occurrence Optimization Electronic Colloquium on Computational Complexity (ECCC) 2003 008 10 db/journals/eccc/eccc10.html#ECCC-TR03-008 http://eccc.hpi-web.de/eccc-reports/2003/TR03-008/index.html