United States. Bureau of Labor Statistics. "National Compensation Survey: Philadelphia-Camden-Vineland, PA-NJ-DE-MD, January 2007 : Bulletin of the United States Bureau of Labor Statistics, No. 3140-07," National Compensation Survey (Wages and Salaries) (September 2007). https://fraser.stlouisfed.org/title/6009/item/582997, accessed on September 14, 2024.