@inproceedings{harry1967on,
title={On inverse problems associated with second-order differential operators},
author={Harry Hochstadt},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203213402758045},
booktitle={Acta Mathematica},
volume={119},
number={1},
pages={173-192},
year={1967},
}
Harry Hochstadt. On inverse problems associated with second-order differential operators. 1967. Vol. 119. In Acta Mathematica. pp.173-192. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20170108203213402758045.