@article{ref1,
title="An analysis of playground surface injuries",
journal="Research quarterly for exercise and sport",
year="1997",
author="Mack, M. G. and Thompson, D. and Hudson, S. M.",
volume="68",
number="4",
pages="368-372",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0270-1367",
doi="",
url="http://dx.doi.org/"
}