@article{ref1,
title="Early development of airborne training",
journal="Military review",
year="1948",
author="Greenfield, K. R. and Palmer, R. R.",
volume="27",
number="12",
pages="27-30",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0026-4148",
doi="",
url="http://dx.doi.org/"
}