|
National Bureau of Economic Research (United States)
52
|
Resources for the Future (United States)
18
|
American Enterprise Institute (United States)
11
|
|
Center for Energy and Environmental Policy Research (United States)
5
|
Centre for Economic Policy Research (United Kingdom)
4
|
Fondazione Eni Enrico Mattei (Italy)
4
|
|
Brookings Institution (United States)
3
|
World Resources Institute (United States)
2
|
Urban Institute (United States)
1
|
