1. Bauersfeld, H., Krummheuer, G., & Voigt, J. (1988). Interactional theory of learning and teaching mathematics and related microethnographical studies. In H.-G. Steiner & A. Vermandel (Eds.), Foundations and methodology of the discipline mathematics education (pp. 174–188). Antwerp, Belgium: University of Antwerp.
2. Blumer, H. (1969). Symbolic interactionism. Englewood Cliffs, NJ: Prentice-Hall.
3. Clements, D. H. (2001). Mathematics in the preschool. Teaching Children Mathematics, 7(5), 270–275.
4. Clements, D. H., Swaminathan, S., Hannibal, M., & Sarama, J. (1999). Young children’s concepts of shape. Journal for Research in Mathematics Education, 30(2), 192–212.
5. Eichler, K.-P. (2007). Ziele hinsichtlich vorschulischer geometrischer Erfahrungen. In J. H. Lorenz & W. Schipper (Eds.), Hendrik Radatz – Impulse für den Mathematikunterricht (pp. 176–185). Braunschweig, Germany: Schroedel.