|
Pembina Institute (Canada)
31
|
American Enterprise Institute (United States)
8
|
National Bureau of Economic Research (United States)
5
|
|
Brookings Institution (United States)
3
|
Centre for Economic Policy Research (United Kingdom)
3
|
World Resources Institute (United States)
3
|
|
Urban Institute (United States)
2
|
Fondazione Eni Enrico Mattei (Italy)
1
|
Mathematica Policy Research (United States)
1
|
|
Resources for the Future (United States)
1
|
