@article {2019,
	title = {From immigrants to robots: The changing locus of substitutes for workers},
	year = {2019},
	institution = {National Bureau of Economic Research},
	address = {Cambridge, MA},
	doi = {10.3386/w25438},
	url = {http://www.nber.org/papers/w25438.pdf},
	author = {Borjas, George and Freeman, Richard}
}
