@article{ref1,
title="The Volume-Density Relation in the Theory of Road Traffic",
journal="Operations research",
year="1960",
author="Haight, Frank A.",
volume="8",
number="4",
pages="572-573",
abstract="[Abstract unavailable]  <p>Language: en</p>",
language="en",
issn="0030-364X",
doi="",
url="http://dx.doi.org/"
}