1. Barretto P. M. C., 1973.Radon-222: Emanation Characteristics of Rocks and Minerals. Department of Mineral Exploration. Brazilian Nuclear Energy Commission, 20 pp.
2. Bilin R. E., 1959,Radon in the New Zealand Geothermal Regions. Geochim. Cosmochim. Acta,16, p. 181–191.
3. Pradel, J. etBillard F., 1959.Le thoron et les risques associés dans la manipulation des composés du thorium. Progress in Nuclear Energy Series XII.1. (Health Physics), p. 239–261.
4. Stoker A. K. etKruger P., 1975,Radon Measurements in Geothermal Systems. Stanford Geothermal Program, Stanford University, Stanford, California. SGP-TR-4, 116 pp.
5. Tanner A. B., 1964,Radon Migration in the Ground: A Review. In:The Natural Radiation Environment. Published for William Marsh Rice University by The University of Chicago Press, p. 161–190.