Boer, Willem den (ed.). Le culte des souverains dans L’empire romain. Entretiens sur l’antiquité classique, 19. Genève: Fondation Hardt, 1973.
This books contains lectures and responses from a number of experts on this topic, including Fergus Millar, Jean Beaujeu, Willem den Boer, and Christian Habicht. Only recently has the view of, e.g., Fergus Millar found acceptance.