@article{ref1,
title="Hearing standards in airline transport pilots",
journal="Journal of aviation medicine",
year="1949",
author="Pothoven, W. J. and Schuringa, A.",
volume="20",
number="3",
pages="171-178",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0095-991X",
doi="",
url="http://dx.doi.org/"
}