@article{ref1,
title="Preliminary impressions of cardiovascular function in the study of physiologic and psychologic aging in professional pilots",
journal="Aerospace medicine",
year="1969",
author="Proper, R.",
volume="40",
number="5",
pages="557-560",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0001-9402",
doi="",
url="http://dx.doi.org/"
}