1. Baroody, A. J. (2003). The development of adaptive expertise and flexibility: The integration of conceptual and procedural knowledge. In A. J. Baroody & A. Dowker (Eds.), The development of arithmetic concepts and skills: Constructing adaptive expertise (pp. 1–33). London, England: Lawrence Erlbaum.
2. Beishuizen, M. (1993). Mental strategies and materials or models for addition and subtraction up to 100 in Dutch second grades. Journal for Research in Mathematics Education, 24, 294–323. doi:
10.2307/749464
.
3. Blöte, A. W., Klein, A. S., & Beishuizen, M. (2000). Mental computation and conceptual understanding. Learning and Instruction, 10, 221–247. doi:
10.1016/S0959-4752(99)00028-6
.
4. Brezovszky, B., Lehtinen, E., McMullen, J., Rodriguez, G., & Veermans, K. (2013). Training flexible and adaptive arithmetic problem solving skills through exploration with numbers. The development of Number Navigation Game. In C. Vaz de Carvalho, & P. Escuderio (Eds.), Proceedings of the 7th European Conference on Game Based Learning (ECGBL2013) (pp. 626–634). Retrieved from
http://issuu.com/acpil/docs/ecgbl2013-issuu_vol_2
5. Canobi, K. H., Reeve, R. A., & Pattison, P. E. (2003). Patterns of knowledge in children’s addition. Developmental Psychology, 39, 521–534. doi:
10.1037/0012-1649.39.3.521
.