@article{ref1,
title="Motor-cyclists, crash helmets, and head injuries",
journal="British medical journal: BMJ",
year="1956",
author="Lewin, W. and Kennedy, W. F.",
volume="1",
number="4978",
pages="1253-1259",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0959-8138",
doi="",
url="http://dx.doi.org/"
}