@techreport{ w13643,
 title = "Voluntary Provision of Public Goods for Bads: A Theory of Environmental Offsets",
 author = "Matthew J. Kotchen",
 institution = "National Bureau of Economic Research",
 type = "Working Paper",
 series = "Working Paper Series",
 number = "13643",
 year = "2007",
 month = "November",
 URL = "http://www.nber.org/papers/w13643",
}