Does Ellroy ever talk about research? If so what are his sources?

I remember someone telling me he got a guy to compile a source history book of the Kennedy assassination for American Tabloid. But in general what are some of his sources? Like Confidential magazine, early true crime books, True Detective magazine, Hollywood Babylon crap like that.

I guess this could also function as a recommendation thread for old/weird/inaccurate non fiction for people to swap niche favorites