Developing a patient-centered outcome measure for complementary and alternative medicine therapies I: defining content and format. - Ritenbaugh C; Nichter M; Nichter MA; Kelly KL; Sims CM; Bell IR; Castañeda HM; Elder CR; Koithan MS; Sutherland EG; Verhoef MJ; Warber SL; et al. (BMC complementary and alternative medicine, 2011)