31 Berggren, W.A. Kent, D.V. Swisher, C.C. III, Aubry, M.-P. 1995 A revised Cenozoic geochronology and chronostratigraphy Berggren, W.A. Kent, D.V. Aubry, M.-P. Hardenbol, J. Geochronology, time scales and global correlation 54 129-212 SEPM Special Publication