David Applegate Robert E. Bixby Vasek Chvátal William Cook Daniel Espinoza Marcos Goycoolea Keld Helsgaun Certification of an optimal TSP tour through 85, 900 cities. 11-15 2009 37 Oper. Res. Lett. 1 http://dx.doi.org/10.1016/j.orl.2008.09.006 db/journals/orl/orl37.html#ApplegateBCCEGH09