@article{ref1,
title="Urban Density and Crowding",
journal="American behavioral scientist",
year="1975",
author="Choldin, H. M.",
volume="18",
number="6",
pages="733-735",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="0002-7642",
doi="10.1177/000276427501800601",
url="http://dx.doi.org/10.1177/000276427501800601"
}