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Hagen EK, Forsberg F, Liu JB, Gomella LG, Aksnes AK, Merton DA, Johnson D, Goldberg BB.Hagen EK, et al. Among authors: merton da.Ultrasound Med Biol. 2001 Jul;27(7):909-13. doi: 10.1016/s0301-5629(01)00394-5.Ultrasound Med Biol. 2001.PMID: 11476923