@article{ref1,
title="Advocacy in public health: roles and challenges",
journal="International journal of epidemiology",
year="2001",
author="Chapman, S.",
volume="30",
number="6",
pages="1226-1232",
abstract="Abstract unavailable.",
language="",
issn="0300-5771",
doi="",
url="http://dx.doi.org/"
}