Ken-ichi Kawarabayashi, Yusuke Kobayashi, Stephan Kreutzer. An excluded half-integral grid theorem for digraphs and the directed disjoint paths problem. In David B. Shmoys, editor, Symposium on Theory of Computing, STOC 2014, New York, NY, USA, May 31 - June 03, 2014. pages 70-78, ACM, 2014. [doi]
Abstract is missing.