@article{ref1,
title="A psychophysical evaluation of the accuracy of shape discrimination as an aircraft landing aid",
journal="Human factors",
year="1971",
author="Kelly, M. J. and Bliss, W. D.",
volume="13",
number="2",
pages="191-193",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0018-7208",
doi="",
url="http://dx.doi.org/"
}