What are some blues "songsters" that I should listen to?

I really want to learn more about old southern blues music. I know a few names, like Son House, Blind Willie McTell, Blind Willie Johnson, and Bessie Smith, but I'd like to expand my knowledge of this genre. I want to listen to the real stuff from the beginnings of this style. I want to listen to the real blues. Any suggestions on who to listen to? Thanks!