United States. Bureau of Labor Statistics. "Area Wage Survey: The Allentown-Bethlehem-Easton, Pennsylvania-New Jersey, Metropolitan Area, May 1972 : Bulletin of the United States Bureau of Labor Statistics, No. 1725-87," Area Wage Survey (1972). https://fraser.stlouisfed.org/title/4655/item/498862, accessed on December 12, 2024.