@article{ref1,
title="Computed distances of legibility of standard traffic control signs",
journal="Journal of the American Optometric Association",
year="1967",
author="Hofstetter, H. W.",
volume="38",
number="5",
pages="381-385",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0003-0244",
doi="",
url="http://dx.doi.org/"
}