Julián, V.; Carrascosa, C.; Corchado, J.M.; Bajo, J.; del Acebo, E.; Innocenti, B.; Botti, V. " Physical agents ." Issues in Multi-Agent Systems. The AgentCities.ES Experience. Moreno, Antonio; Pavón, Juan (Eds.): Whitestein Series in Software Agent Technologies an. (NLD): Springer-Verlag, 2008.