@article{ref1,
title="How many concussions are too many?",
journal="CMAJ : Canadian Medical Association journal",
year="1999",
author="Kent, H.",
volume="160",
number="6",
pages="884-884",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0820-3946",
doi="",
url="http://dx.doi.org/"
}