@article{Brownson2009,
author = {Brownson, R.C. and Hoehner, C.M. and Day, K. and Forsyth, A. and Sallis, J.F. },
title= {Measuring the built environment for physical activity: State of the science},
year = {2009},
doi = {10.2148/benv.35.1.122},
journal = {American Journal of Preventive Medicine },
volume = {36},
number = {4s},
pages = {S99−S123},
}