@article{kao_chen_huang_shen_2014,  title={Using a least squares support vector machine to estimate a local geometric geoid model},  volume={20},  ISSN={1982-2170},  url={https://doi.org/10.1590/S1982-21702014000200025},  DOI={10.1590/S1982-21702014000200025},  number={2},  journal={Boletim de Ciências Geodésicas},  publisher={Universidade Federal do Paraná},  author={Kao, Szu-Pyng and Chen, Chao-Nan and Huang, Hui-Chi and Shen, Yu-Ting},  year={2014},  month={Apr},  pages={427–443} }