Howard J. Karloff Subhash Khot Aranyak Mehta Yuval Rabani On earthmover distance, metric labeling, and 0-extension Electronic Colloquium on Computational Complexity (ECCC) 2005 064 db/journals/eccc/eccc12.html#TR05-064 http://eccc.hpi-web.de/eccc-reports/2005/TR05-064/index.html