@article{ref1,
title="Task difficulty and the efficiency of muscular activity",
journal="Journal of applied psychology",
year="1972",
author="Vidacek, S. and Wishner, J.",
volume="56",
number="6",
pages="510-512",
abstract="<p>[Abstract unavailable]</p><p>Language: en</p>",
language="en",
issn="0021-9010",
doi="",
url="http://dx.doi.org/"
}