U/Pb Zircon Geochronology and Tempo of the End-Permian Mass Extinction Bowring, S. A. ; Erwin, D. H. ; Jin, Y. G. ; Martin, M. W. ; Davidek, K. ; Wang, W. Abstract Publication: Science Pub Date: May 1998 DOI: 10.1126/science.280.5366.1039 Bibcode: 1998Sci...280.1039B