@article{ref1,
title="Sleep and activity: their relation to the 24-hour clock",
journal="Research publications - Association for Research in Nervous and Mental Disease",
year="1967",
author="Richter, C. P.",
volume="45",
number="",
pages="8-29",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0091-7443",
doi="",
url="http://dx.doi.org/"
}