@inproceedings { santos18, booktitle = {in Proc. of AAAI 2018 (student track)}, keywords = {Multi-Agent Societies;Game Theory;}, series = {student track}, title = { Indirect Reciprocity and Costly Reputation Building in Multiagent Systems }, volume = {student track}, year = {2018}, author = {Fernando P. Santos and Jorge M. Pacheco and Francisco C. Santos} }