The Environment and Directed Technical Change
NBER Working Paper No. 15451
---- Acknowledgements -----
We thank Robert Barro, Emmanuel Farhi, Elhanan Helpman, David Laibson, Per Krusell, Ariel Pakes, Torsten Persson, Nicholas Stern, Nancy Stokey and Martin Weitzman for very helpful suggestions. We also benefited from the comments of seminar and conference participants at Harvard, MIT, Stanford, Berkeley, IIES in Stockholm, Zurich, the NBER Summer Institute, the Midwest macro conference, the Canadian Institute for Advanced Research, the Latin American Meeting of the Econometric Society, and Simon Fraser University. The views expressed herein are those of the author(s) and do not necessarily reflect the views of the National Bureau of Economic Research.