@article{ref1,
title="Hours of work and shiftwork",
journal="Ergonomics",
year="1976",
author="Rutenfranz, J. and Knauth, P. and Colquhoun, W. P.",
volume="19",
number="3",
pages="331-340",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0014-0139",
doi="",
url="http://dx.doi.org/"
}