1. Baroody, A.J. (1984). The case of Felicia: A young child’s strategies for reducing memory demands during mental addition. Cognition and Instruction, 1 (1), 109 – 116.
2. Baroody, A.J. & Gannon, K.E. (1984) The development of the commutativity principle and economical addition strategies. Cognition and Instruction, 1 (3), 321– 339.
3. Evertsz, R., Hennessy, S., Devi, R. (1988). GADL: A Graphical Interface for Mental Arithmetic Algorithms. CITE Report No. 49, The Open University. Gelman, R. (1977). How young children reason about small numbers. In N. J. Castellan et al. (eds.), Cognitive Theory, vol. 2. Hillsdale, NJ: Erlbaum. Gelman, R. & Gallistel, CR. (1978).
4. The Child’s Understanding of Number. Cambridge, Mass.:
5. Harvard University Press. Hennessy, S. (1986). The role of conceptual knowledge in the acquisition of arithmetic algorithms. PhD thesis. University College, London.