I have revised and updated versions of two working papers on the Social Science Research Network. They will both be published later this year in Daniel H. Cole and Elinor Ostrom, Property in Land and Other Resources (Cambridge, Mass.: Lincoln Institute of Land Policy, 2011):
"The Variety of Property Systems and Rights in Natural Resources" (with Elinor Ostrom) (available for download here).
"Property Creation by Regulation: Rights to Clean Air and Rights to Pollute" (available for download here).