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Cohen A, Shoup RE.Cohen A, et al. Among authors: shoup re.Percept Psychophys. 1993 Jun;53(6):693-703. doi: 10.3758/bf03211745.Percept Psychophys. 1993.PMID: 8332435
Sun YP, Smith DL, Shoup RE.Sun YP, et al. Among authors: shoup re.Anal Biochem. 1991 Aug 15;197(1):69-76. doi: 10.1016/0003-2697(91)90357-y.Anal Biochem. 1991.PMID: 1952077