@article{ref1,
title="The eye at altitude",
journal="International ophthalmology clinics",
year="1999",
author="Butler, F. K.",
volume="39",
number="2",
pages="59-78",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0020-8167",
doi="",
url="http://dx.doi.org/"
}