@unpublished{publication-5208,
	author={Darai, Donja and Gr{\"a}tz, Silvia},
	institution={University of Zurich},
	number={No. 1006},
	series={Working paper series / Socioeconomic Institute},
	title={Determinants of Successful Cooperation in a Face-to-Face Social Dilemma},
	year=2010,
}