@article{ref1,
title="Energy consumption in hand and motor driven plows",
journal="Arbeitsphysiologie",
year="1953",
author="Hettinger, T. and Wirths, W.",
volume="15",
number="1",
pages="41-46",
abstract="<p>[Abstract unavailable]</p><p>Language: un</p>",
language="un",
issn="0365-0863",
doi="",
url="http://dx.doi.org/"
}