@article{ref1,
title="Single number measures of hearing protector noise reduction",
journal="Occupational health nursing",
year="1979",
author="Berger, E. H.",
volume="27",
number="8",
pages="22-23",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0029-7933",
doi="",
url="http://dx.doi.org/"
}