@article{sirisathitkul_glawtanong_eadkong_sirisathitkul_2013,  title={Digital video analysis of falling objects in air and liquid using Tracker},  volume={35},  ISSN={1806-1117},  url={https://doi.org/10.1590/S1806-11172013000100020},  DOI={10.1590/S1806-11172013000100020},  number={1},  journal={Revista Brasileira de Ensino de Física},  publisher={Sociedade Brasileira de Física - SBF},  author={Sirisathitkul, C. and Glawtanong, P. and Eadkong, T. and Sirisathitkul, Y.},  year={2013},  month={Jan},  pages={1–6} }