@article{ref1,
title="Psychophysical studies of physiological fatigue criteria",
journal="Human factors",
year="1969",
author="Irvine, C. H. and Snook, S. H.",
volume="11",
number="3",
pages="291-300",
abstract="Abstract unavailable.",
language="",
issn="0018-7208",
doi="",
url="http://dx.doi.org/"
}