Niv Buchbinder Tracy Kimbrel Retsef Levi Konstantin Makarychev Maxim Sviridenko Online make-to-order joint replenishment model: primal dual competitive algorithms. 952-961 2008 SODA http://doi.acm.org/10.1145/1347082.1347186 conf/soda/2008 db/conf/soda/soda2008.html#BuchbinderKLMS08