@article{ref1,
title="Physical fitness, exercise, and human sleep",
journal="Psychophysiology",
year="1978",
author="Griffin, S. J. and Trinder, J.",
volume="15",
number="5",
pages="447-450",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0048-5772",
doi="",
url="http://dx.doi.org/"
}