Noga Alon Benny Sudakov Uri Zwick Constructing Worst Case Instances for Semidefinite Programming Based Approximation Algorithms. 58-72 2001 15 SIAM J. Discrete Math. 1 http://epubs.siam.org/sam-bin/dbq/article/37971 db/journals/siamdm/siamdm15.html#AlonSZ01