@article{ref1,
title="Sports injury research. The numerator, denominator, and the population-at-risk",
journal="American journal of sports medicine",
year="1988",
author="Wallace, R. B. and Clark, W. R.",
volume="16",
number="Suppl 1",
pages="S55-6",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0363-5465",
doi="",
url="http://dx.doi.org/"
}