United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "December 1987," Business Conditions Digest (December 1987) : 1-1. https://fraser.stlouisfed.org/title/43/item/7496/toc/189527 , accessed on April 19, 2024.
United States. Bureau of the Census. "Cover Page," in United States. Bureau of the Census. "December 1987," Business Conditions Digest (December 1987) : 1-1. https://fraser.stlouisfed.org/title/43/item/7496/toc/189527 , accessed on April 19, 2024.