@article{ref1,
title="Bicycle safety helmet usage in Berlin 1999: an observational study",
journal="Sozial und Praventivmedizin",
year="2002",
author="Saul, Nadine and Kurzawski, Sandra and Boose, Ruth and Bohning, D.",
volume="47",
number="2",
pages="124-127",
abstract="Abstract unavailable.",
language="",
issn="0303-8408",
doi="",
url="http://dx.doi.org/"
}