1. M. Andrews: Hardness of buy-at-bulk network design, in: Proceedings of the 45th Annual Symposium on Foundations of Computer Science, pages 115–124, Rome, Italy, October 2004.
2. M. Andrews, J. Chuzhoy, S. Khanna and L. Zhang: Hardness of the undirected edge-disjoint paths problem with congestion, in: Proceedings of the 46th Annual IEEE Symposium on Foundations of Computer Science, pages 226–244, 2005.
3. M. Andrews and L. Zhang: Hardness of the undirected edge-disjoint paths problem, in: Proceedings of the 37th Annual ACM Symposium on Theory of Computing, pages 276–283, 2005.
4. M. Andrews and L. Zhang: Hardness of the undirected congestion minimization problem, in: Proceedings of the 37th Annual ACM Symposium on Theory of Computing, pages 284–293, 2005.
5. M. Andrews and L. Zhang: Hardness of the edge-disjoint paths problem with congestion, Manuscript, 2005. Available at: ]http://ect.bell-labs.com/who/dmandrews/publications/edp-congestion.ps .