@article{Huang1998,
author = {Huang, Y. and Macera, C.A. and Blair, S.N. and Brill, P.A. and Kohl, A.W.},
title= {Physical fitness, physical activity and functional limitation in adults aged 40 and older},
year = {1998},
doi = {10.1097/00005768-199809000-00013},
journal = {Medicine and Science in Sports and Exercise},
volume = {30},
number = {9},
pages = {1430--1435},
}