@article{ref1,
title="Risk factors for drug overdose mortality",
journal="International journal of epidemiology",
year="1993",
author="Berg, J. E.",
volume="22",
number="6",
pages="1204-1205",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0300-5771",
doi="",
url="http://dx.doi.org/"
}