Kamal JainMohammad MahdianEvangelos MarkakisAmin SaberiVijay V. VaziraniGreedy Facility Location Algorithms Analyzed using Dual Fitting with Factor-Revealing LPhttps://arxiv.org/abs/cs/02070282002CoRRcs.DS/0207028db/journals/corr/corr0207.html#cs-DS-0207028