Hoffmann, M. H., Lenhard, J., & Seeger, F. (2005). Activity and Sign: Grounding Mathematics Education. Springer Science+Business Media, Inc.
Chicago Style (17th ed.) CitationHoffmann, Michael H.G, Johannes Lenhard, and Falk Seeger. Activity and Sign: Grounding Mathematics Education. Boston, MA: Springer Science+Business Media, Inc, 2005.
MLA (8th ed.) CitationHoffmann, Michael H.G, et al. Activity and Sign: Grounding Mathematics Education. Springer Science+Business Media, Inc, 2005.
Warning: These citations may not always be 100% accurate.