The History Place
The History Place: The Triumph of Hitler: Night of the Long Knives
Describes the problems Hitler had bringing the brown-shirted SA storm troopers under his control and the events during the Night of the Long Knives when SS death squads executed SA leaders across the country.
Wikimedia
Wikipedia: Dictatorship
A short article on the nature of 20th century dictatorship. It provides examples of dictatorships such as Nazi Germany and Fascist Italy.