Eriksson, I., J. Fred, A.-K. Nordin, M. Nyman, and S. Wettergren. “Tasks, Tools, and Mediated Actions – Promoting Collective Theoretical Work on Algebraic Expressions”. NOMAD Nordic Studies in Mathematics Education, vol. 26, no. 3-4, Oct. 2021, pp. 29–52, doi:10.7146/nomad.v26i3-4.149169.