Federal Reserve Bank of Chicago. "The Chicago Area - An Economic Perspective," in Federal Reserve Bank of Chicago. "Annual Report 1967 : The Chicago Area - An Economic Perspective," Annual Report of the Federal Reserve Bank of Chicago (February 23, 1968) : 11-50. https://fraser.stlouisfed.org/title/472/item/529821/toc/517561 , accessed on April 25, 2024.