@article{ref1,
title="History of legal aspects of enforcing minimum headways",
journal="Public health reviews",
year="1987",
author="Frischer, J.",
volume="15",
number="4",
pages="347-349",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0301-0422",
doi="",
url="http://dx.doi.org/"
}