@article{ref1,
title="Safe parachute descent; an unsolved problem",
journal="Journal of aviation medicine",
year="1949",
author="Smedal, H. A. and Webster, A. P.",
volume="20",
number="6",
pages="443-447",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0095-991X",
doi="",
url="http://dx.doi.org/"
}