The first model of strong reciprocity was proposed by Herbert Gintis in 2000, which contained a number of simplifying assumptions addressed in later models.
Strong Medicine | Four Year Strong | Augustus II the Strong | Tara Strong | Tom Strong | Strong Poison | Strong's Concordance | Strong Bad | William Duncan Strong | Strong-billed Honeyeater | Strong AI | An American Girl: Chrissa Stands Strong | Strong Vincent | Strong Arm Steady | Maurice Strong | Mark Strong | Brenda Strong | Ted Strong | Strong Tower | Strong City, Kansas | Strong | Stretch Arm Strong | Something So Strong | Simon Strong | Reciprocity | Pritchard-Strong Company | Mr. Dingle, the Strong | Mary Strong Clemens | John Strong Newberry | James Strong (theologian) |