@article{garcia_sotomayor_2005,  title={On the patterns of principal curvature lines around a curve of umbilic points},  volume={77},  ISSN={0001-3765},  url={https://doi.org/10.1590/S0001-37652005000100002},  DOI={10.1590/S0001-37652005000100002},  number={1},  journal={Anais da Academia Brasileira de Ciências},  publisher={Academia Brasileira de Ciências},  author={Garcia, Ronaldo and Sotomayor, Jorge},  year={2005},  month={Mar},  pages={13–24} }