@article{ref1,
title="Absence from work in relation to the length and distribution of shift hours",
journal="British journal of preventive and social medicine",
year="1970",
author="Walker, J.",
volume="24",
number="1",
pages="61-61",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0007-1242",
doi="",
url="http://dx.doi.org/"
}