@article{chalub_2009,  title={The Saros cycle: obtaining eclipse periodicity from Newton's laws},  volume={31},  ISSN={1806-1117},  url={https://doi.org/10.1590/S1806-11172009000100003},  DOI={10.1590/S1806-11172009000100003},  number={1},  journal={Revista Brasileira de Ensino de Física},  publisher={Sociedade Brasileira de Física - SBF},  author={Chalub, Fabio A.C.C.},  year={2009},  month={Apr},  pages={1303.1–1303.6} }