@article{ref1,
title="Crowds and Violence: Negotiating with Mobs",
journal="Journal of police crisis negotiations",
year="2009",
author="Penn, Brooke E. and Cooper, H. H.A.",
volume="9",
number="1",
pages="3-33",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="1533-2586",
doi="10.1080/15332580802493914",
url="http://dx.doi.org/10.1080/15332580802493914"
}