Radon therapy for the treatment of rheumatic diseases–review and meta-analysis of controlled clinical trials

Falkenbach A1, Kovacs J, Franke A, Jörgens K, Ammer K
Rheumatol Int. 2005 Apr;25(3):205-10. Epub 2003 Dec 12

https://www.ncbi.nlm.nih.gov/pubmed/14673618