United States. Bureau of the Census. "April 1987," Business Conditions Digest (April 1987). https://fraser.stlouisfed.org/title/43/item/7488, accessed on April 18, 2024.
United States. Bureau of the Census. "April 1987," Business Conditions Digest (April 1987). https://fraser.stlouisfed.org/title/43/item/7488, accessed on April 18, 2024.