@article{ref1,
title="Incidence density is no density",
journal="Scandinavian journal of social medicine",
year="1993",
author="Karhausen, L. R.",
volume="21",
number="1",
pages="1-2",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0300-8037",
doi="10.1177/140349489302100101",
url="http://dx.doi.org/10.1177/140349489302100101"
}