@article{ref1,
title="Some effects of sleep deprivation",
journal="Activitas nervosa superior",
year="1969",
author="Kogan, A. B.",
volume="11",
number="3",
pages="256-258",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0001-7604",
doi="",
url="http://dx.doi.org/"
}