Widrig R, Suter A, Saller R, Melzer J (2007). «Choosing between NSAID and arnica for topical treatment of hand osteoarthritis in a randomised, double-blind study». Rheumatol. Int.27 (6): 585-91. PMID17318618. doi:10.1007/s00296-007-0304-y.|fechaacceso= requiere |url= (ayuda)
Widrig R, Suter A, Saller R, Melzer J (2007). «Choosing between NSAID and arnica for topical treatment of hand osteoarthritis in a randomised, double-blind study». Rheumatol. Int.27 (6): 585-91. PMID17318618. doi:10.1007/s00296-007-0304-y.|fechaacceso= requiere |url= (ayuda)