Classification of platelet concentrates (Platelet-Rich Plasma-PRP, Platelet-Rich Fibrin-PRF) for topical and infiltrative use in orthopedic and sports medicine: current consensus, clinical implications and perspectives - Dohan Ehrenfest, D M; Andia, I; Zumstein, M A; Zhang, C-Q; Pinto, N R; Bielecki, T (Muscles Ligaments Tendons J, 2014)