United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "March 1972," Business Conditions Digest (March 1972) : 76-76. https://fraser.stlouisfed.org/title/43/item/7564/toc/378592 , accessed on April 25, 2024.
United States. Bureau of the Census. "Foreign Trade," in United States. Bureau of the Census. "March 1972," Business Conditions Digest (March 1972) : 76-76. https://fraser.stlouisfed.org/title/43/item/7564/toc/378592 , accessed on April 25, 2024.