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June 1989

March 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).

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).

http://www.j-bradford-delong.net/pdf_files/Unit_Root.pdf