1. www.stratigraphy.org/geowhen/stages/Pleistocene.html.
2. Gibbard P. Annual Report of the Subcommission on Quaternary Stratigraphy in the ICS Annual Report for 2007 (www.stratigraphy.org/report07.pdf).
3. Follow link to Global Boundary Stratotype Sections and Points at www.stratigraphy.org/.
4. I thank S. Finney for pointing me in the right direction for an update on the Holocene issue.