Szukana fraza: [Abstract = "Therefore, they must start a negotiation dialogue, taking also into account that they might have incomplete or wrong beliefs about the other agent`s goals and resources. This article presents a negotiating agent model based on argumentation, which is used by the agents to reason on how to exchange resources and knowledge in order to achieve their goals. Agents that negotiate have incomplete beliefs about the others, so that the exchange of arguments gives them information that makes it possible to update their beliefs."]