[2] P C P Fernandes, W O Sousa, L M Q C Julião et al. Development and validation of a technique for the determination of 226Ra and 228Ra by liquid scintillation in liquid samples. Radiation Protection Dosimetry, 144, 335-338(2010).

[3] F Carvalho, D Chambers, S Fernandes et al. The environmental behaviour of radium: revised edition. IAEA technical reports series No.476, 1-5(2014).

[4] Shoupeng ZHU, Zhang LI. Radiotoxicology, 268-269(2004).

[6] A J Kordyasz, B Bartós, A Bilewicz. Simultaneous determination of 224Ra and 226Ra isotopes by measuring of emanated 220Rn and 222Rn using a 4-inch silicon epitaxial detector. Chemia Analityczna, 49, 29-39(2004).

[10] G G Jia, J Jia. Determination of radium isotopes in environmental samples by gamma spectrometry, liquid scintillation counting and alpha spectrometry: a review of analytical methodology. Journal of Environmental Radioactivity, 106, 98-119(2012).

[11] M A Ajemigbitse, F S Cannon, N R Warner. A rapid method to determine 226Ra concentrations in Marcellus Shale produced waters using liquid scintillation counting. Journal of Environmental Radioactivity, 220/221, 106300(2020).

[12] B B Sadi, C S Li, G H Kramer et al. Rapid determination of 226Ra in drinking water samples using dispersive liquid-liquid microextraction coupled with liquid scintillation counting. Journal of Radioanalytical and Nuclear Chemistry, 290, 415-425(2011).

[13] M Cook, R Kleinschmidt. Simultaneous determination of 226Ra and 228Ra in water by liquid scintillation spectrometry. Australian Journal of Chemistry, 64, 880-884(2011).

[15] K Sato, T Hashimoto, M Noguchi et al. A simple method for determination of 226Ra in environmental samples by applying α-β coincidence liquid scintillation counting. Journal of Environmental Radioactivity, 48, 247-256(2000).

[16] S Jowzaee. Determination of selected natural radionuclide concentrations in southwestern Caspian groundwater using liquid scintillation counting. Radiation Protection Dosimetry, 157, 234-241(2013).

[17] J M Godoy, L M Vianna, M L D P Godoy et al. Determination of 226Ra in produced water by liquid scintillation counting. Journal of Environmental Radioactivity, 160, 25-27(2016).

[19] N D Chau, J Niewodniczański, J Dorda et al. Determination of radium isotopes in mine waters through alpha- and beta-activities measured by liquid scintillation spectrometry. Journal of Radioanalytical and Nuclear Chemistry, 222, 69-74(1997).

[20] M Villa, H P Moreno, G Manjón. Determination of 226Ra and 224Ra in sediments samples by liquid scintillation counting. Radiation Measurements, 39, 543-550(2005).

[21] H P Moreno, I Vioque, G Manjón et al. An easy method for Ra-226 determination in river waters by liquid-scintillation counting. Czechoslovak Journal of Physics, 49, 467-472(1999).