@article{ref1,
title="Human operator response speed, frequency, and flexibility: a review and analysis",
journal="Human factors",
year="1967",
author="Wargo, M. J.",
volume="9",
number="3",
pages="221-238",
abstract="Abstract unavailable.",
language="",
issn="0018-7208",
doi="",
url="http://dx.doi.org/"
}