United States. Bureau of Labor Statistics. "Area Wage Survey: The Allentown-Bethlehem-Easton, Pennsylvania-New Jersey, Metropolitan Area, May 1971 : Bulletin of the United States Bureau of Labor Statistics, No. 1685-75," Area Wage Survey (1971). https://fraser.stlouisfed.org/title/4655/item/498736, accessed on December 12, 2024.