@article{tang_he_andam-akorful_2014,  title={The performance of bds relative positioning usage with real observation data},  volume={20},  ISSN={1982-2170},  url={https://doi.org/10.1590/S1982-21702014000200014},  DOI={10.1590/S1982-21702014000200014},  number={2},  journal={Boletim de Ciências Geodésicas},  publisher={Universidade Federal do Paraná},  author={Tang, Xu and He, Xiufeng and Andam-Akorful, Samuel A.},  year={2014},  month={Apr},  pages={223–236} }