APA
Goulder L. H., Williams R. C., . (1999). The usual excess-burden approximation usually doesn't come close. Cambridge, Mass: National Bureau of Economic Research.
Chicago
Goulder Lawrence H, Williams Roberton C, . 1999. The usual excess-burden approximation usually doesn't come close. Cambridge, Mass: National Bureau of Economic Research.
Harvard
Goulder L. H., Williams R. C., . (1999). The usual excess-burden approximation usually doesn't come close. Cambridge, Mass: National Bureau of Economic Research.
MLA
Goulder Lawrence H, Williams Roberton C, . The usual excess-burden approximation usually doesn't come close. Cambridge, Mass: National Bureau of Economic Research. 1999.