1. Physical Characteristics of Radon 222 Emanation from Rocks, Soils and Minerals: Its relation to temperature and alpha dose;Barretto,1983
2. Radon from Gravel and Aggregate — Method and consequences to indoor air;Hildingson;National Testing Institute of Sweden, Technical report 1983,1984
3. Meteorological influences upon the radon-content of soilgas;Kovach;Transaction. American Geophysical Union,1945
4. Radon in soil — Exhalation/soil water ratio, seasonal fluctuations, permeability;Lindmark;Swedish geotechnical institute, Report No 24,1984
5. Radon migration in the ground. A supplementary review;Tanner;U.S. Geological survey, Open-file Report 78–1050,1978