Alok Baveja Aravind Srinivasan Approximating low-congestion routing and column-restricted packing problems. 19-25 2000 74 Inf. Process. Lett. 1-2 db/journals/ipl/ipl74.html#BavejaS00 http://dx.doi.org/10.1016/S0020-0190(00)00033-8