1. Bergstrom, T., Blume, L., and Varian, H., 1986. “On the private provision of public goods,” Journal of Public Economies, 29, 25–49.
2. Bryan, J.H. and Test, M.A., 1967. “Models and helping: naturalistic studies in aiding behavior”, Journal of Personality and Social Psychology, 6, 400–7.
3. Buchanan, J.M., 1967. “Conflict and cooperation in public goods interaction”, Western Economic Journal, 5, 109–21.
4. Cornes, R., and Sandier, T., 1983. “On commons and tragedies”, American Economic Review, 73, 787–92.
5. Cornes, R. and Sandier, T., 1984. “The theory of public goods: non-Nash behavior”, Journal of Public Economics, 18, 367–79.