@article{ref1,
title="Double crew continuous flying operations: a study of aircrew sleep patterns",
journal="Aerospace medicine",
year="1970",
author="Atkinson, D. W. and Borland, R. G. and Nicholson, A. N.",
volume="41",
number="10",
pages="1121-1126",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0001-9402",
doi="",
url="http://dx.doi.org/"
}