@article{ref1,
title="Letter from ... Denmark. Problems of prevention",
journal="British medical journal: BMJ",
year="1975",
author="Frolund, F.",
volume="3",
number="5986",
pages="760-761",
abstract="Abstract unavailable.",
language="",
issn="0959-8138",
doi="",
url="http://dx.doi.org/"
}