Philadelphia : Industrial Research Unit, Wharton School of Finance and Commerce, University of Pennsylvania; distributed by University of Pennsylvania Press, 1970
Philadelphia : Industrial Research Unit, Wharton School of Finance and Commerce, University of Pennsylvania; distributed by University of Pennsylvania Press, 1970
Philadelphia : Industrial Research Unit, Wharton School of Finance and Commerce, University of Pennsylvania; distributed by University of Pennsylvania Press, 1970
Philadelphia : Industrial Research Unit, Wharton School of Finance and Commerce, University of Pennsylvania; distributed by University of Pennsylvania Press, 1970-1971
Philadelphia : Industrial Research Unit, Wharton School of Finance and Commerce, University of Pennsylvania; distributed by University of Pennsylvania Press, 1971-1972