@article{ref1,
title="Vision at levels of night road illumination",
journal="Highway Research Board bulletin",
year="1952",
author="Richards, Oscar W.",
volume="56",
number="",
pages="36-65",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0073-2206",
doi="",
url="http://dx.doi.org/"
}