@article{ref1,
title="Bias when using dead controls to study handgun purchase as a risk factor for violent death",
journal="Injury prevention",
year="2003",
author="Wiebe, Douglas J. and Branas, Charles C.",
volume="9",
number="4",
pages="381-382",
abstract="Abstract unavailable.",
language="en",
issn="1353-8047",
doi="",
url="http://dx.doi.org/"
}