@article{ref1,
title="Road and urban transportation in Bulgaria",
journal="IATSS research",
year="1990",
author="Todorov, T",
volume="14",
number="2",
pages="42-53",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="0386-1112",
doi="",
url="http://dx.doi.org/"
}