Beta Klotho is required for metabolic activity of fibroblast growth factor 21 - Ogawa, Y; Kurosu, H; Yamamoto, M; Nandi, A; Rosenblatt, K P; Goetz, R; Eliseenkova, A V; Mohammadi, M; Kuro-o, M (Proc Natl Acad Sci U S A, 2007)