Nikhil Bansal Amit Chakrabarti Amir Epstein Baruch Schieber A quasi-PTAS for unsplittable flow on line graphs. 721-729 2006 conf/stoc/2006 STOC http://doi.acm.org/10.1145/1132516.1132617 db/conf/stoc/stoc2006.html#BansalCES06