@article{ref1,
title="Evaluation of the protective characteristics of helmets in sports",
journal="Journal of trauma",
year="1964",
author="Gurdjian, Elisha S. and Hodgson, Volgt R. and Hardy, W. G. and Patrick, L. M. and Lissner, H. R.",
volume="171",
number="",
pages="309-324",
abstract="",
language="",
issn="0022-5282",
doi="",
url="http://dx.doi.org/"
}