Fernando Lopes Augusto Q. Novais Helder Coelho Bilateral Negotiation in a Multi-Agent Energy Market. 655-664 2009 ICIC (1) http://dx.doi.org/10.1007/978-3-642-04070-2_71 conf/icic/2009-1 db/conf/icic/icic2009-1.html#LopesNC09