@article{ref1,
title="Evaluation of head protection in aircraft",
journal="Aerospace medicine",
year="1969",
author="Ewing, C. L. and Irving, A. M.",
volume="40",
number="6",
pages="596-599",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0001-9402",
doi="",
url="http://dx.doi.org/"
}