@article{ref1,
title="Concussions in soccer: use your head--but not as a weapon",
journal="World neurosurgery",
year="2012",
author="Sonntag, Volker K. H.",
volume="78",
number="5",
pages="431-432",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="1878-8750",
doi="10.1016/j.wneu.2011.12.064",
url="http://dx.doi.org/10.1016/j.wneu.2011.12.064"
}