1. Isotopic constitution of radiogenic lead and the measurement of geological time;Collins;Bul. Geol. Ser. Amer.,1954
2. Economic Geol. Sun.;Ellsworth,1932
3. The isolation of actinium;Hageman;J. Amer. Chem. Soc.,1950
4. Radon leakage from radioactive minerals;Guletti;Amer. Min.,1955
5. Calculating the age of minerals from the radioactivity data and principles;Liovarik;Natl. Res. Counc. Bul.,1931