@article{ref1,
title="Warning of visual impairment",
journal="JAMA journal of the American Medical Association",
year="1975",
author="Bergen, R. P.",
volume="231",
number="10",
pages="1086-1086",
abstract="Abstract unavailable.",
language="",
issn="0098-7484",
doi="",
url="http://dx.doi.org/"
}