@article{ref1,
title="Spurious effects from an extraneous variable",
journal="Journal of chronic diseases",
year="1966",
author="Bross, I. D.",
volume="19",
number="6",
pages="637-647",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0021-9681",
doi="",
url="http://dx.doi.org/"
}