@article{ref1,
title="Philadelphia's New Program for Traffic Signal Modernization",
journal="Traffic quarterly",
year="1956",
author="Butterfield, SF",
volume="10",
number="2",
pages="268-268",
abstract="[Abstract unavailable]  <p>Language: en</p>",
language="en",
issn="0041-0713",
doi="",
url="http://dx.doi.org/"
}