I particularly liked and studied:
Theory: Deterding et al, Csikszentmihaly on flow, Koster on fun (some) Mcgonigal (some), I have heard about Mary-Jo kim, Werbach, Lazzaro.
Actual studies, none that I am truly impressed with, as in studies that deal with what I call complex gamification beyond PBL (points, badges, leaderboards). Currently following Yukai Chou a self-prescribed pioneer. He has good info.
Any thoughts, ideas, or things about gamification you have found meaningful particularly relating to education?