@article{ref1,
title="Periodontal trauma in youth",
journal="Deutsche Zahnarztliche Zeitschrift",
year="1965",
author="Mueller, G. H. and Overdiek, H. F.",
volume="20",
number="",
pages="94-105",
abstract="<p>[Abstract unavailable]</p><p>Language: de</p>",
language="de",
issn="0012-1029",
doi="",
url="http://dx.doi.org/"
}