@inproceedings{evgeny2009k-normal,
title={k-NORMAL SURFACES},
author={Evgeny Fominykh, and Bruno Martelli},
url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20160911182605392030770},
booktitle={Journal of Differential Geometry},
volume={82},
number={1},
pages={101-114},
year={2009},
}