United States. Bureau of Labor Statistics. "Area Wage Survey: Allentown-Bethlehem-Easton, Pennsylvania-New Jersey, Metropolitan Area, May 1973 : Bulletin of the United States Bureau of Labor Statistics, No. 1775-90," Area Wage Survey (1973). https://fraser.stlouisfed.org/title/4655/item/498993, accessed on December 12, 2024.