Bitzer, D.L., W. Lichtenberger & P.G. Braunfeld, "PLATO II: A multiple-student computer controlled teaching machine"

Programmed Learning and Computer-based Instruction (1962) Programmed Learning and Computer-based Instruction, ed. by Coulson, John Wiley & Sons, NY, 1962  

Languages mentioned TUTOR {1974} Scripting for CAI