Employment and Earnings Statistics for the United States, 1909-68 : Bulletin of the United States Bureau of Labor Statistics, No. 1312-6
United States. Bureau of Labor Statistics. "Employment and Earnings Statistics for the United States, 1909-68 : Bulletin of the United States Bureau of Labor Statistics, No. 1312-6," Employment and Earnings, United States (1968). https://fraser.stlouisfed.org/title/189/item/497665, accessed on March 28, 2024.