@article{ref1,
title="The use of Boolean algebra in safety",
journal="Journal of safety research",
year="1972",
author="Brown, D. B.",
volume="4",
number="4",
pages="155-159",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0022-4375",
doi="",
url="http://dx.doi.org/"
}