@article{ref1,
title="The protective effects of helmets in skiers and snowboarders",
journal="British medical journal: BMJ",
year="2011",
author="Ruedl, Gerhard and Kopp, Martin and Burtscher, Martin",
volume="342",
number="online",
pages="d857-d857",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0959-8138",
doi="10.1136/bmj.d857",
url="http://dx.doi.org/10.1136/bmj.d857"
}