@article{ref1,
title="A definition of the safety measurement problem",
journal="Journal of safety research",
year="1970",
author="Tarrants, WE",
volume="2",
number="3",
pages="106-108",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0022-4375",
doi="",
url="http://dx.doi.org/"
}