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Liu GC, Ahrens EH Jr, Schreibman PH, Samuel P, McNamara DJ, Crouse JR.Liu GC, et al. Among authors: schreibman ph.Proc Natl Acad Sci U S A. 1975 Nov;72(11):4612-6. doi: 10.1073/pnas.72.11.4612.Proc Natl Acad Sci U S A. 1975.PMID: 1060141Free PMC article.