@article{ref1,
title="Protective helmet for pilots of high-speed aircraft",
journal="Journal of aviation medicine",
year="1948",
author="Hendler, E. and Poppen, J. R.",
volume="19",
number="6",
pages="420-425",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0095-991X",
doi="",
url="http://dx.doi.org/"
}