@article{ref1,
title="Physical activity in children. U.S. Public Health Service",
journal="American family physician",
year="1994",
author="",
volume="50",
number="6",
pages="1285-1288",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0002-838X",
doi="",
url="http://dx.doi.org/"
}