@article{ref1,
title="Coloring teeth black in Japan",
journal="Quintessenz journal",
year="1985",
author="Holtkamp, P.",
volume="15",
number="9",
pages="843-844",
abstract="<p>[Abstract unavailable]</p><p>Language: de</p>",
language="de",
issn="0033-6599",
doi="",
url="http://dx.doi.org/"
}