@article{ref1,
title="Helmet. No. 2,457,554",
journal="Journal of the patent office society",
year="1948",
author="Harding, H. C.",
volume="43",
number="",
pages="UNKNOWN-UNKNOWN",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0096-3577",
doi="",
url="http://dx.doi.org/"
}