@article{ref1,
title="Classification and sources in environmental safety and health",
journal="Annals of occupational hygiene",
year="1973",
author="Reid, A. S.",
volume="16",
number="3",
pages="257-265",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0003-4878",
doi="",
url="http://dx.doi.org/"
}