Approximation, Randomization, and Combinatorial Optimization. Algorithms and Techniques 14th International Workshop, APPROX 2011, and 15th International Workshop, RANDOM 2011, Princeton, NJ, USA, August 17-19, 2011. Proceedings - Goldberg, Leslie Ann; Jansen, Klaus; Ravi, R.; Rolim, José D. P. (Springer Berlin Heidelberg : Imprint: Springer, 2011)