@InProceedings{vbsv-2008,
  title = 	 {Ascending Auctions for Integral (Poly)-Matroids with Concave Nondecreasing Separable Values},
  author = 	 {Sven de Vries and Sushil Bikhchandani and James Schummer and Rakesh V. Vohra},
  booktitle = {Proceedings of the nineteenth annual ACM-SIAM symposium on discrete algorithms (SODA)},
  pages = 	 {864--873},
  url= {http://portal.acm.org/citation.cfm?id=1347177},
  year = 	 2008}