@inproceedings{donald1984a,
title={A new proof of a sharp inequality concerning the Dirichlet integral},
author={Donald E. Marshall},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203529466412507},
booktitle={Arkiv for Matematik},
volume={27},
number={1},
pages={131-137},
year={1984},
}
Donald E. Marshall. A new proof of a sharp inequality concerning the Dirichlet integral. 1984. Vol. 27. In Arkiv for Matematik. pp.131-137. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203529466412507.