Sources principales :

The Haight-Ashbury: A history par Charles Perry.
Cité par Colin Pringle
Copyright © 1995, 1996, Colin Pringle

Hippies From A to Z par Skip Stone, webmaster de Hippy.com.
Copyright 1999, Skip Stone.
http://www.hippy.com/

The Chronology of Digger
http://www.digger.com

The Sixties: A Journey Through the Decade
http://www.ronaldreaganweb.com/thesixties/index.htm

A timeline of the counterculture
http://www.well.com/user/mareev/TIMELINE/Max 

Elbaum Political Chronology 1954-1992
http://www.revolutionintheair.com/chron/chron1.html