@article{ref1,
title="Relationships among measures of activity in children",
journal="Journal of pediatric psychology",
year="1982",
author="Kivlahan, Daniel R. and Siegel, L. J. and Ullman, D. G.",
volume="7",
number="3",
pages="331-344",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0146-8693",
doi="",
url="http://dx.doi.org/"
}