10.Danesch UC. Petasites hybridus (Butterbur root) extract in the treatment of asthma–an open trial. Altern Med Rev. 2004 Mar;9(1):54-62. http://www.altmedrev.com/publications/9/1/54.pdf
10.Danesch UC. Petasites hybridus (Butterbur root) extract in the treatment of asthma–an open trial. Altern Med Rev. 2004 Mar;9(1):54-62. http://www.altmedrev.com/publications/9/1/54.pdf