@article{jaeggi2016reciprocal,
  author = {Jaeggi, Adrian V and Hooper, Paul L and Beheim, Bret A and Kaplan, Hillard and Gurven, Michael},
  title = {Reciprocal exchange patterned by market forces helps explain cooperation in a small-scale society},
  journal = {Current Biology},
  year = {2016},
  volume = {26},
  number = {16},
  pages = {2180--2187},
  doi = {10.1016/j.cub.2016.06.019}
}