W. Affolter, G. Baerli, H. Hurschler, B. Jaggi, W. Jundt et al., Mathbu.ch 7, 2003.

B. Zug,

T. P. Carpenter, L. Levi, M. L. Franke, and J. Koehler-zeringue, Algebra in elementary school: Developing relational thinking, ZDM, vol.37, issue.1, pp.53-59, 2005.

H. Freudenthal, Mathematics as an educational task, Reidel, 1973.

T. Fujii and M. Stephens, Fostering an understanding of algebraic generalization through numerical expressions: The role of quasi-variables, Proceedings of the 12 th ICMI Study Conference: The future of the teaching and learning of algebra, pp.258-364, 2001.

C. Kieran, Overall commentary on early algebraization: Perspectives for research and teaching, Early algebraization. A Global Dialogue from Multiple Perspectives, pp.579-593, 2011.

D. Küchemann, Children's understanding of mathematics, pp.102-119, 1981.

D. Lenz, Relational thinking and operating on unknown quantities, Proceedings of the 2015 joint conference of ProMath and the GDM working group on problem solving, pp.173-181, 2016.
URL : https://hal.archives-ouvertes.fr/hal-02416379

D. Melzig, Unpublished Doctoral dissertation), 2013.

M. Molina, R. Ambrose, E. Castro, and E. Castro, Breaking the addition addiction: creating the conditions for knowing-to act in early algebra, Mathematical Action & Structures Of Noticing: Studies inspired by John Mason, pp.121-134, 2009.

L. Radford, Early algebraization. A Global Dialogue from Multiple Perspectives, pp.303-322, 2011.

A. D. Schliemann, D. W. Carraher, and B. M. Brizuela, Bringing out the algebraic character of arithmetic: From children's ideas to classroom practice, 2007.

H. Spiegel and C. Selter, Wie Kinder rechnen, 1997.

A. S. Steinweg, K. Akinwunmi, and D. Lenz, Teaching and Learning Algebraic Thinking with 5-to 12-Year-Olds: The Global Evaluation of an Emerging Field of Research and Practice, pp.283-307, 2018.

M. Stephens and X. Wang, Investigating some junctures in relational thinking: A study of year 6 and year 7 students from Australia and China, Journal of Mathematics Education, vol.1, issue.1, pp.28-39, 2008.

Z. Usiskin, Conceptions of school algebra and uses of variables, The ideas of algebra, pp.8-19, 1988.