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Wallny TA, Schild RL, Schulze Bertelsbeck D, Hansmann ME, Kraft CN.Wallny TA, et al.Ultrasound Med Biol. 2001 Jun;27(6):745-9. doi: 10.1016/s0301-5629(01)00361-1.Ultrasound Med Biol. 2001.PMID: 11516533