@article{ref1,
title="Friction in Road Surfaces",
journal="Deutsche Medizinische Wochenschrift",
year="1934",
author="Graf, O and Weil, G",
volume="78",
number="",
pages="856-858",
abstract="[Abstract unavailable]  <p>Language: en</p>",
language="en",
issn="0012-0472",
doi="",
url="http://dx.doi.org/"
}