@article{ref1,
title="Early post-concussional headache",
journal="Lancet",
year="1970",
author="Tubbs, O. N. and Potter, J. M.",
volume="2",
number="7664",
pages="128-129",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0140-6736",
doi="",
url="http://dx.doi.org/"
}