1. Boeckmann, H. (1971). The Discovery Approach Strategy for Mathematics Teachers. School science and Mathematics, 71(1), 3-6. https://doi.org/10.1111/j.1949-8594.1971.tb09833.x
2. Cheung, P. H. (Link). Problem-solving strategies: Research findings from mathematics Olympiads. Department of Curriculum Studies. The University of Hong Kong, p. 80. Retrieved from http://sms.math.nus.edu.sg/smsmedley/Vol-20-2/Problem-solving%20strategies%20-%20research%20findings%20from%20Mathematics%20Olympiad(PH%20Cheung).pdf
3. Dewey, J. (1933). How we think: A restatement of the relation of reflective thinking to the educational process. Boston, MA: D.C. Heath and Co.
4. Lester, F., & Charles, R. I. (Eds.) (2003). Teaching mathematics through problem solving: Pre- K- grade. Reston, VA: National Council for Teachers of Mathematics.
5. National Council for Teachers of Mathematics (2000). Principles and standards for school mathematics. Reston, VA: National Council for Teachers of Mathematics.