J. Bradford DeLong (1992), "Machinery Investment as a Key to American Economic Growth"
J. Bradford DeLong (1992), "Machinery Investment as a Key to American Economic Growth," in Mark Bloomfield, Margo Thorning, and Charls Walker, eds., Tools for American Workers (Washington, DC: American Council for Capital Formation).
http://www.j-bradford-delong.net/movable_type/pdf_files/ACCF.pdf
