@article{ref1,
title="Impossible policy evaluations and impossible conclusions: a comment on Koper and Roth",
journal="Journal of quantitative criminology",
year="2001",
author="Kleck, Gary D.",
volume="17",
number="1",
pages="75-80",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0748-4518",
doi="10.1023/A:1007574415289",
url="http://dx.doi.org/10.1023/A:1007574415289"
}