United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "September 1987," Business Conditions Digest (September 1987) : 1-1. https://fraser.stlouisfed.org/title/43/item/7493/toc/218875 , accessed on April 23, 2024.
United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "September 1987," Business Conditions Digest (September 1987) : 1-1. https://fraser.stlouisfed.org/title/43/item/7493/toc/218875 , accessed on April 23, 2024.