@article{ref1,
title="Does play fighting have a function",
journal="Aggressive behavior",
year="1988",
author="Einon, D",
volume="14",
number="2",
pages="128-128",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0096-140X",
doi="",
url="http://dx.doi.org/"
}