3Hopper KD ,Bird DE, Reddy VV, et al. Efficacy of automated biopsy guns versus conventional biopsy needles in the pygmy nig. Radiology. 1990,176: 671-676.
4Elvin A ,Andersson T, Scheibenpflug, et al . Biopsy of the pancrease witha biopsy gun . Radiology. 1990. 176:677-679.