@article{ref1,
title="Commentary: Matched cohorts can be useful",
journal="British medical journal: BMJ",
year="2003",
author="Evans, Stephen",
volume="326",
number="7385",
pages="357-357",
abstract="<p>Comments on: BMJ. 2002;324(7346):1119-1122; and BMJ. 2003;326(7385):357. </p> <p>Language: en</p>",
language="en",
issn="0959-8138",
doi="",
url="http://dx.doi.org/"
}