@article{ref1,
title="Rest and activity patterns for prolonged extraterrestrial missions",
journal="Aerospace medicine",
year="1972",
author="Nicholson, A. N.",
volume="43",
number="3",
pages="253-257",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0001-9402",
doi="",
url="http://dx.doi.org/"
}