@article{ref1,
title="Circadian variation of sleep tendency in elderly and young adult subjects",
journal="Sleep",
year="1982",
author="Dement, W. C. and Orav, E. John and Carskadon, Mary A. and Richardson, G. S.",
volume="5",
number="Suppl 2",
pages="S82-94",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0161-8105",
doi="",
url="http://dx.doi.org/"
}