3 ms·http://cowles.econ.yale.edu/P/cd/d19a/d1934.pdf http://cowles.econ.yale.edu/P/cd/d19a/d1934.pdfby pcvarmint 13y agohttp://cowles.econ.yale.edu/P/cd/d19a/d1934.pdf http://cowles.econ.yale.edu/P/cd/d19a/d1934.pdf