APA (7e ed.) Bronvermelding

Hoffmann, M. H., Lenhard, J., & Seeger, F. (2005). Activity and Sign: Grounding Mathematics Education. Springer US. https://doi.org/10.1007/b105055

Chicago (17e ed.) Bronvermelding

Hoffmann, Michael H.G, Johannes Lenhard, en Falk Seeger. Activity and Sign: Grounding Mathematics Education. Boston, MA: Springer US, 2005. https://doi.org/10.1007/b105055.

MLA (9e ed.) Bronvermelding

Hoffmann, Michael H.G, et al. Activity and Sign: Grounding Mathematics Education. Springer US, 2005. https://doi.org/10.1007/b105055.