Geraldo, R.R., Paschuk, S.A., Barreto, R.C., Corrêa, J.N., Zahn, G.S., Cardoso da Silva, P.S., Malagi da Silva, A.C., Narloch, D.C. and Araujo, I.C. 2021. Application of semi-empirical model for the evaluation of radium activity in phosphogypsum used as component of clinker. Brazilian Journal of Radiation Sciences. 9, 1A (Apr. 2021). DOI:https://doi.org/10.15392/bjrs.v9i1A.1518.