Sutter, Matthias Max Planck Institute for Research on Collective Goods, Max Planck Society;
https://doi.org/10.1628/093245606777583503 (beliebiger Volltext)
Güth, W., Sutter, M., & Verbon, H. (2006). Voluntary versus Compulsory Solidarity: Theory and Experiment. JITE - Journal of Institutional and Theoretical Economics, 162, 347-363.