BiTrust: A Comprehensive Trust Management Model for Multi-agent Systems -- Using Reference Points for Competitive Negotiations in Service Composition -- A Cooperative Framework for Mediated Group Decision Making -- A CPN-Based Protocol for Concurrent Multiple Negotiation -- A Dependency-based Mediation Mechanism for Complex Negotiations -- Using graph properties and clustering techniques to select division mechanisms for scalable negotiations -- Compromising Strategy considering Interdependencies of Issues for Multi-issue Closed Nonlinear Negotiations.