@article{ref1,
title="Football: the pre-season examination",
journal="Journal of sports medicine",
year="1973",
author="Clayton, M. L. and Hamlin, C. and Lewis, M. D.",
volume="1",
number="4",
pages="19-24",
abstract="<p>[Abstract unavailable]  Keywords: American football; </p> <p>Language: en</p>",
language="en",
issn="0090-4201",
doi="",
url="http://dx.doi.org/"
}