, 2010, Historical artefacts, semiotic mediation and teaching proof, in G. Hanna, H. N. Jahnke & H. Pulte (eds.), Explanation and proof in mathematics, Dordrecht, Springer, pp. 151-167.
with Ferri, F. , 2005a, Semiotic mediation in the primary school, in M. H. G. . Hoffmann, J. Lenhard & F. Seeger (eds.), Activity and sign, Dordrecht, Springer, pp. 77-90.