Edmundo P. Leiva-Lobos Eliana Covarrubias The 3-Ontology: A Framework to Place Cooperative Awareness. 189-202 2002 conf/criwg/2002 CRIWG http://dx.doi.org/10.1007/3-540-46124-8_13 db/conf/criwg/criwg2002.html#Leiva-LobosC02