@article{ref1,
title="Spring-operated semiautomatic irrigation valves",
journal="Transactions of the American Society of Agricultural and Biological Engineers",
year="1983",
author="Young, DA and Oest, E and Humpherys, AS",
volume="26",
number="1",
pages="134-140",
abstract="Torsion spring operators for standard low pressure butterfly type irrigation valves are described. Usually these devices present little risk of injury. However, there can be considerable risk of injury under certain common conditions.<p />",
language="",
issn="0001-2351",
doi="",
url="http://dx.doi.org/"
}