@article{ref1,
title="An elementary ambiguity in accident theory",
journal="Accident analysis and prevention",
year="1973",
author="Kemp, C. D.",
volume="5",
number="4",
pages="371-373",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0001-4575",
doi="",
url="http://dx.doi.org/"
}