@article{ref1,
title="Aircraft periscopes for pilotage",
journal="Journal of aviation medicine",
year="1955",
author="Emerson, G. O.",
volume="26",
number="2",
pages="121-123",
abstract="<p>[Abstract unavailable]</p> <p>Language: en</p>",
language="en",
issn="0095-991X",
doi="",
url="http://dx.doi.org/"
}