Klose, R., & Schreiber, C..  (2018).  TellMEE - Telling Mathematics in Elementary Education. In C.  Benz, Steinweg, A. Susanne, Gasteiger, H., Vollmuth, H., Schöner, P., & Zöllner, J. (Hrsg.), Early Mathematics Learning ? Selected Papers of the POEM Conference 2016 (S. 159-177). New York: Springer.

Kortenkamp, U., Brandt, B., Benz, C., Krummheuer, G., Ladel, S., & Vogel, R. (Hrsg.).  (2013).  Early Mathematics Learning. Selected Papers of the POEM 2012 Conference. New York: Springer.

Ladel, S., & Kortenkamp, U..  (2013).  Number Concepts - Process of Internalization and Externalization by the Use of Multi-Touch Technology. In U.  Kortenkamp, Brandt, B., Benz, C., Krummheuer, G., Ladel, S., & Vogel, R. (Hrsg.), Early Mathematics Learning. Selected Papers of the POEM 2012 Conference. (S. 237-253). New York: Springer.