@article{Clark1998,
author = {Clark, D.O. and Stump, T.E. and Wolinsky, F.D.},
title= {Predictors of onset of and recovery from mobility difficulty among adults aged 51-61 years},
year = {1998},
journal = {American Journal of Epidemiology},
volume = {148},
number = {1},
pages = {63--71},
}