@article{ref1,
title="A study of vertical motion requirements for landing simulation",
journal="Human factors",
year="1973",
author="Bray, R. S.",
volume="15",
number="6",
pages="561-568",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0018-7208",
doi="",
url="http://dx.doi.org/"
}