@article{ref1,
title="Energy expenditure of pilots flying cargo aircraft",
journal="Aerospace medicine",
year="1970",
author="Kaufman, W. C. and Callin, G. D. and Harris, C. E.",
volume="41",
number="6",
pages="591-596",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0001-9402",
doi="",
url="http://dx.doi.org/"
}