1. State of the art: uranium mining, milling and refining industry;Clark,1974
2. Statistical data of the uranium industry;Grand Junction Office, U.S.A.E.C.,1973
3. Safety in uranium mining and milling;Hurst;Nucl. Safety,1962
4. Radiation hazards in uranium mines and mills;Johnson,1960
5. The solubility of pure radium sulfate;Lind;J. Am. Chem. Soc.,1918