1. Proceedings of the Second Special Symposium on Natural Radiation Environment held at Bombay;Gragnani,1982
2. Misure della concentrazione di radioisotopi naturali nei carboni e nelle ceneri di carbone;ENEL,1983
3. Report of the United Nation Scientific Committee on the Effect of Ionizing Radiation;UNSCEAR,1982
4. Behavior of natural radionuclides in western coal-fired power plants