@book{505263,
	author = {Costa, D.L.},
	title = {Hours of work and the fair labor standards act: a study of retail and wholesale trade, 1938-1950},
	publisher = {National Bureau of Economic Research},
	year = {1998},
	address = {Cambridge},
	url = {http://www.econ.ucla.edu/costa/flsaillr.pdf}
}