Swallow, Brent M.; Wangila, Justine; Mulatu, Woudyalew; Okello, Onyango; McCarthy, Nancy(CGIAR System-wide Program on Property Rights and Collective Action, International Food Policy Research Institute, Washington, DC, 2000)
Baland, Jean-Marie; Francois, Patrick(Leverhulme Centre for Market and Public Organisation, Department of Economics, University of Bristol, Bristol, United Kingdom, 2003)