@article{ref1,
title="Play aggression among Zapotec children: implications for the practice hypothesis",
journal="Aggressive behavior",
year="1990",
author="Fry, DP",
volume="16",
number="5",
pages="321-340",
abstract="<p>[Abstract unavailable]</p>",
language="en",
issn="0096-140X",
doi="",
url="http://dx.doi.org/"
}