@article{ref1,
title="Human circadian rhythms in resting and exercise pulse rates",
journal="Ergonomics",
year="1977",
author="Cohen, C. J. and Muehl, G. E.",
volume="20",
number="5",
pages="475-479",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0014-0139",
doi="10.1080/00140137708931656",
url="http://dx.doi.org/10.1080/00140137708931656"
}