@article{ref1,
title="Butting heads over bicycle helmets",
journal="CMAJ : Canadian Medical Association journal",
year="2002",
author="DeMarco, TJ",
volume="167",
number="4",
pages="337; author reply 338-9",
abstract="Abstract unavailable.",
language="",
issn="0820-3946",
doi="",
url="http://dx.doi.org/"
}