@article{ref1,
title="An analysis of the demand for emergency ambulance service in an urban area",
journal="American journal of public health",
year="1971",
author="Aldrich, C. A. and Hisserich, J. C. and Lave, L. B.",
volume="61",
number="6",
pages="1156-1169",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0090-0036",
doi="",
url="http://dx.doi.org/"
}