@article{ponge-ferreira_koskinas_dias_2004,  title={Standardization of Ca-45 radioactive solution by tracing method},  volume={34},  ISSN={0103-9733},  url={https://doi.org/10.1590/S0103-97332004000500062},  DOI={10.1590/S0103-97332004000500062},  number={3a},  journal={Brazilian Journal of Physics},  publisher={Sociedade Brasileira de Física},  author={Ponge-Ferreira, Cláudia Regina Ponte and Koskinas, Marina Fallone and Dias, Mauro da Silva},  year={2004},  month={Sep},  pages={939–941} }