1. J. Magil, J. Galy: Radioactivity, Radionuclides. Radiation (Springer Heidelberg 2005)
2. M. S. Mustapha, A. S. Bukhari, H. E. S. Mohamed: Environmental Radioactivity (LAP Lambert Academic Publications 2011)
3. https://www.britannica.com/science/radioactivity
4. https://de.wikipedia.org/wiki/Radioaktivit%C3%A4t
5. https://www.sciencedirect.com/topics/earth-and-planetary-sciences/natural-radioactivity