@article{ref1,
title="Data collection and observer bias",
journal="Annals of emergency medicine",
year="1990",
author="Petri, R. W. and Wears, Robert",
volume="19",
number="5",
pages="614-614",
abstract="Abstract unavailable.",
language="",
issn="0196-0644",
doi="",
url="http://dx.doi.org/"
}