@misc{Cromartie2017,
author = {Cromartie, J. and Parker, T.},
title= {Rural classifications},
year = {2017},
URL = {http://www.ers.usda.gov/topics/rural-economy-population/rural-classifications/what-is-rural.aspx#.UtWLlPvAbng},
publisher = {Economic Research Service, US Department of Agriculture},
address = {Washington, D.C.},
}