Encyclopedia Britannica
Encyclopedia Britannica: 300 Women Who Changed History: Ann Lee
Encyclopaedia Britannica provides a biography of Ann Lee (1736-1784), founder of the parent Shaker settlement in America in the woods of Niskeyuna, N.Y.
PBS
Pbs: The Shakers Timeline
A good timeline showing the major events in the history of the religious group plus it also places them in the context of events around the world.