1. Abelson, H. & diSessa, A. A. (1981). Turtle geometry: The computer as medium for exploring mathematics. Cambridge, MA: MIT Press.
2. Barr, A. & Feigenbaum, E. A. (Eds.). (1982). The handbook of artificial intelligence (Vol. 2). Los Altos, CA: William Kaufmann.
3. Boyer, E. L. (1983). High school: A report on secondary education in America. New York: Harper & Row.
4. Boyle, C. F. & Anderson, J. R. (1984, April). Acquisition and automated instruction of geometry proof skills. Paper presented at the annual meeting of the American Educational Research Associatio? New Orleans, LA.