@article{ref1,
title="Effect of effort on ballistocardiographic curve",
journal="Acta physiologica polonica",
year="1954",
author="Bober, S.",
volume="5",
number="3",
pages="291-301",
abstract="<p>[Abstract unavailable]</p><p>Language: pl</p>",
language="pl",
issn="0044-6033",
doi="",
url="http://dx.doi.org/"
}