Katsutoshi Hirayama Toshihiro Matsui Makoto Yokoo Adaptive price update in distributed Lagrangian relaxation protocol. 1033-1040 2009 AAMAS (2) http://doi.acm.org/10.1145/1558109.1558157 conf/atal/2009-2 db/conf/atal/aamas2009-2.html#HirayamaMY09