@article{ref1,
title="Accident analysis at railroad-highway grade crossings in urban areas",
journal="Accident analysis and prevention",
year="1969",
author="Berg, WD and Oppenlander, JC",
volume="1",
number="2",
pages="129-141",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0001-4575",
doi="",
url="http://dx.doi.org/"
}