@article{norbert_2011,  title={The derivation of algorithms to compute elliptic integrals of the first and second kind by Landen-transformation},  volume={17},  ISSN={1982-2170},  url={https://doi.org/10.1590/S1982-21702011000100001},  DOI={10.1590/S1982-21702011000100001},  number={1},  journal={Boletim de Ciências Geodésicas},  publisher={Universidade Federal do Paraná},  author={Norbert, Rösch},  year={2011},  month={Jan},  pages={03–22} }