2007, Long-term benefit of radon spa therapy in the rehabilitation of rheumatoid arthritis: a randomised, double-blinded trial

Franke A, Reiner L, Resch KL

Rheumatol Int. 2007 Jun;27(8):703-13. Epub 2007 Jan 4

https://www.ncbi.nlm.nih.gov/pubmed/17203297