1. Bartell, T. G., Webel, C., Bowen, B., & Dyson, N. (2013). Prospective teacher learning: recognizing evidence of conceptual understanding. Journal of Mathematics Teacher Education, 16(1), 57–79.
2. Beckmann, S. (2018). Mathematics for elementary teachers with activities (5th ed.). New York, NY: Pearson.
3. Behr, M., Lesh, R., Post, T., & Silver, E. (1983). Rational number concepts. In R. Lesh & M. Landau (Eds.), Acquisition of mathematics concepts and processes (pp. 91–125). New York: Academic Press.
4. Behr, M. J., Post, T. R., & Wachsmuth, I. (1986). Estimation and children’s concept of rational number size. In H. L. Schoen (Ed.), Estimation and mental computation (pp. 103–111). Reston, VA: NCTM.
5. Behr, M. J., Wachsmuth, I., & Post, T. R. (1985). Construct a sum: A measure of children’s understanding of fraction size. Journal for Research in Mathematics Education, 16(2), 120–131.