@misc{Ruggles2015,
author = {Ruggles, S. and Genadek, K. and Goeken, R. and Grover, J. and Sobek, M.},
title= {Integrated Public Use Microdata Series: Version 6.0 [Machine-readable database]},
year = {2015},
publisher = {University of Minnesota},
address = {Minneapolis},
}