@article{ref1,
title="Terrain-following with a head-up display",
journal="Human factors",
year="1968",
author="Soliday, S. M. and Milligan, J. R.",
volume="10",
number="2",
pages="117-126",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0018-7208",
doi="",
url="http://dx.doi.org/"
}