Hyung-Chan An, Robert Kleinberg, David B. Shmoys. Improving christofides' algorithm for the s-t path TSP. In Howard J. Karloff, Toniann Pitassi, editors, Proceedings of the 44th Symposium on Theory of Computing Conference, STOC 2012, New York, NY, USA, May 19 - 22, 2012. pages 875-886, ACM, 2012. [doi]
Abstract is missing.