J. Bradford DeLong and Lawrence H. Summers, "On the Existence and Interpretation of a `Unit Root' in U.S. Real GDP" (Cambridge, MA: Harvard University Department of Economics, 1989).
J. Bradford DeLong and Lawrence H. Summers, "On the Existence and Interpretation of a `Unit Root' in U.S. Real GDP" (Cambridge, MA: Harvard University Department of Economics, 1989).
