@article{ref1,
title="High school football injuries: a pilot comparison of playing surfaces",
journal="Medicine and science in sports",
year="1972",
author="Bramwell, S. T. and Requa, R. K. and Garrick, J. G.",
volume="4",
number="3",
pages="166-169",
abstract="<p>[Abstract unavailable]  Keywords: American football; </p> <p>Language: en</p>",
language="en",
issn="0025-7990",
doi="",
url="http://dx.doi.org/"
}