zalasiewicz=et al.=2008-are we now living in the anthropocene?.pdf

wilmarth=1925=the geologic time classification of the united states geological survey compared with other classifications, accompanied by the original definitions of era, period and epoch terms.pdf

subrt=2001=the problem of time from the perspective of the social sciences.pdf

reiners=riihimaki=heffern=2011=clinker geochronology, the first glacial maximum, and landscape evolution in the northern rockies.pdf

macdonald=et al.=2010=calibrating the cryogenian.pdf

knoll=walter=narbonne=christie-blick=2006=the ediacaran period; a new addition to the geological time scale.pdf

kerr=2008=two geologic clocks finally keeping the same time.pdf

Geologic Time Scale Official 2004.pdf

cooper=nowlan=williams=global stratotype section and point for base of the ordovician system.pdf

cooper=2004=NZ Geological Timescale.pdf