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The superoxide dismutase molecular clock revisited.
Fitch WM, Ayala FJ. Fitch WM, et al. Proc Natl Acad Sci U S A. 1994 Jul 19;91(15):6802-7. doi: 10.1073/pnas.91.15.6802. Proc Natl Acad Sci U S A. 1994. PMID: 8041700 Free PMC article.