Primal-Dual Approximation Algorithms for Integral Flow and Multicut in Trees, with Applications to Matching and Set Cover.

Naveen Garg Vijay V. Vazirani Mihalis Yannakakis Primal-Dual Approximation Algorithms for Integral Flow and Multicut in Trees, with Applications to Matching and Set Cover. 64-75 1993 conf/icalp/1993 ICALP db/conf/icalp/icalp93.html#GargVY93 http://dx.doi.org/10.1007/3-540-56939-1_62