@article{Hall2006,
author = {Hall, S.A. and Kaufman, J.S. and Ricketts, T.C.},
title= {Defining urban and rural areas in US epidemiologic studies},
year = {2006},
doi = {10.1007/s11524-005-9016-3},
volume = {83},
number = {2},
pages = {162--175},
}