S. Shaheen Fatima Michael Wooldridge Nicholas R. Jennings An analysis of feasible solutions for multi-issue negotiation involving nonlinear utility functions. 1041-1048 2009 AAMAS (2) http://doi.acm.org/10.1145/1558109.1558158 conf/atal/2009-2 db/conf/atal/aamas2009-2.html#FatimaWJ09