@article{optimalboundsonapproximationofsubmodular,
  title = {Optimal Bounds on Approximation of Submodular and XOS Functions by Juntas},
  author = {Vitaly Feldman and Jan Vondrak},
  year = {2013},
  eprint = {1307.3301},
  archivePrefix = {arXiv},
  url = {http://arxiv.org/abs/1307.3301v3},
}