@article{ref1,
title="Head-Up Display Symbology for Ground Collision Avoidance",
journal="International journal of aviation psychology",
year="2001",
author="Billingsley, Geoffrey and Kuchar, James K. and Jacobson, Steven W.",
volume="11",
number="1",
pages="33-51",
abstract="[Abstract unavailable]  <p>Language: en</p>",
language="en",
issn="1050-8414",
doi="10.1207/S15327108IJAP1101_3",
url="http://dx.doi.org/10.1207/S15327108IJAP1101_3"
}