2014, A review of halotherapy for chronic obstructive pulmonary disease.

Rashleigh R, Smith S.MS, Roberts NJ

Int.J. Chron Obstruct Pulmon Dis. 2014; 9:239-246. doi: 10.2147/COPD.S57511.

(PMC free article)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3937102/