@article { santos21, journal = {Nature Sustainability}, keywords = {Multi-Agent Societies;Game Theory;}, pages = {https://doi.org/10.1038/s41893-020-00667-2}, title = {Dynamics of informal risk-sharing in collective index insurance}, year = {2021}, author = {Fernando P. Santos and Jorge M. Pacheco and Francisco C. Santos and Simon A. Levin} }