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"Voluntarily Separable Prisoner's Dilemma with Reference Letters"
Fujiwara-Greve, Takako, (2008)
"Social Norms and Voluntary Cooperations"(in Japanese)
Okuno-Fujiwara, Masahiro, (2007)
Voluntarily separable repeated Prisonerʼs Dilemma with reference letters
Fujiwara-Greve, Takako, (2012)