@unpublished{publication-5542,
	author={Fischbacher, Urs and G{\"a}chter, Simon},
	institution={University of Zurich},
	issn={1424-0459},
	number={No. 261},
	series={Working paper series / Institute for Empirical Research in Economics},
	title={Heterogeneous social preferences and the dynamics of free riding in public goods},
	year=2006,
}