@article{ref1,
title="Twenty Years of Homicide and Robbery inChicago: The Impact of the City's Changing Racial and Age Composition",
journal="Journal of quantitative criminology",
year="1987",
author="Chilton, R.",
volume="3",
number="",
pages="195-214",
abstract="<p>[Abstract unavailable]</p>",
language="",
issn="0748-4518",
doi="",
url="http://dx.doi.org/"
}