1. Soil gas radon—a source for indoor radon daughters;Akerblom;Radiation Protection Dosimetry,1984
2. Areas in the United States with elevated screening levels of 222Rn;Alexander;Health Physics,1994
3. The radiological impact of agricultural activities in an area of high natural radioactivity;Amaral,1992
4. Measurement of natural radiation in hot spring areas in West Java;Annaliah,1993