@article{ref1,
title="Nonlinear truck factor for two-lane highways",
journal="Transportation research record",
year="1976",
author="St John, A. D.",
volume="615",
number="",
pages="49-53",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0361-1981",
doi="",
url="http://dx.doi.org/"
}