United States. Bureau of Labor Statistics. "National Compensation Survey: Philadelphia-Wilmington-Atlantic City, PA-NJ-DE-MD, August 1999 : Bulletin of the United States Bureau of Labor Statistics, No. 3100-29," National Compensation Survey (Wages and Salaries) (June 2000). https://fraser.stlouisfed.org/title/6009/item/582404, accessed on January 23, 2025.