@article{ref1,
title="Portable bulb-type changeable message signs for highway work zones",
journal="ITE journal",
year="1988",
author="",
volume="58",
number="4",
pages="17-20",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="0162-8178",
doi="",
url="http://dx.doi.org/"
}