@inproceedings{plamen2009local,
title={LOCAL LENS RIGIDITY WITH INCOMPLETE DATA FOR A CLASS OF NON-SIMPLE RIEMANNIAN MANIFOLDS},
author={Plamen Stefanov, and Gunther Uhlmann},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20160911184019964911778},
booktitle={Journal of Differential Geometry},
volume={82},
number={2},
pages={383-409},
year={2009},
}

Plamen Stefanov, and Gunther Uhlmann. LOCAL LENS RIGIDITY WITH INCOMPLETE DATA FOR A CLASS OF NON-SIMPLE RIEMANNIAN MANIFOLDS. 2009. Vol. 82. In Journal of Differential Geometry. pp.383-409. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20160911184019964911778.