@article{ref1,
title="Concussion in sports",
journal="American family physician",
year="1999",
author="Terrell, T. R. and Tucker, A. M.",
volume="60",
number="3",
pages="738, 741-2",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0002-838X",
doi="",
url="http://dx.doi.org/"
}