Short paths in expander graphs. Approximation algorithms for Steiner and directed multicuts. Faster approximation algorithms for the unit capacity concurrent flow problem with applications to routing and finding sparse cuts. Philip Klein and R. Ravi. Stavros G. Kolliopoulos and Clifford Stein.
Fast approximation algorithms for multicommodity flow problems.
An approach to emulating separable graphs. New approximation techniques for some ordering problems. Huzur Saran and Vijay V. Vazirani. Finding k cuts within twice the optimal. Daniel A. Spielman and Shang-Hua Teng.