United States. Bureau of Labor Statistics. "Delaware," in United States. Bureau of Labor Statistics. "Employment, Hours, and Earnings, States and Areas, 1972-87 : Bulletin of the United States Bureau of Labor Statistics, No. 2320," Employment, Hours, and Earnings, States and Areas (March 1989) : 434-461. https://fraser.stlouisfed.org/title/245/item/5876/content/pdf/bls_eestates_1972to1987_v1/toc/400055 , accessed on March 29, 2024.