1. Adi, H. (1978). Intellectual development and reversibility of thought in equation solving. Journal for Research in Mathematics Education, 9, 204–213.
2. Biddlecomb, B., & Olive, J. (2000). JavaBars [Computer software]. Retrieved from
http://math.coe.uga.edu/olive/welcome.html
3. Carpenter, T. P., Fennema, E., Franke, M. L., Levi, L., & Empson, S. B. (1999). Children’s mathematics: Cognitively guided instruction. Portsmouth, NH: Heinemann.
4. Carpenter, T. P., Fennema, E., Peterson, P. L., & Carey, D. A. (1988). Teachers’ pedagogical content knowledge of students’ problem solving in elementary arithmetic. Journal for Research in Mathematics Education, 19, 385–401.
5. Carpenter, T. P., & Moser, J. M. (1983). The acquisition of addition and subtraction concepts. In R. Lesh & M. Landau (Eds.), Acquisition of mathematics concepts and processes (pp. 7–44). New York: Academic.