In terms of American Fascism, i've written this post previously and i'd suggest those books I referenced. American Fascists, Nazis and Neo-Nazis have been responsible for plenty of violence in the United States, racially and otherwise. I'd also suggest Hoods and Shirts: The Extreme Right in Pennsylvania, 1925-1950 by Philip Jenkins, a good overview of the varied Far Right political groups and their actions in the Pre-War to Post-War period.