@article{ref1,
title="Matched cohort methods for injury research",
journal="Epidemiologic reviews",
year="2003",
author="Cummings, Peter and McKnight, Barbara and Greenland, Sander",
volume="25",
number="",
pages="43-50",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0193-936X",
doi="",
url="http://dx.doi.org/"
}