@article {14548, title = {Approximation Algorithms for Non-Uniform Buy-at-Bulk Network Design}, journal = {SIAM Journal on Computing}, volume = {39}, year = {2010}, month = {2010///}, pages = {1772 - 1798}, author = {Chekuri,C. and Hajiaghayi, Mohammad T. and Kortsarz,G. and Salavatipour,M. R} }