Wow. That's the problem, there aren't any I can recommend. I know what I know because as part of my research elsewhere I read Southern (and other) newspapers from the 1870s,80s, 90s, 1900s, 1910s and 20s everyday. But what I've read I am sure you have never heard about. That period is nothing like they teach in school. As for violence it was most probably worse than anything I could have imagined. The political parties were behind it, no doubt.