@book{ BA91570060, author = "Radford, Luis and Schubring, Gert and Seeger, Falk", title = "Semiotics in mathematics education : epistemology, history, classroom, and culture", publisher = "Sense Publishers", year = "2008", series = "Semiotic perspectives in the teaching and learning of mathematics series", number = "1", URL = "https://ci.nii.ac.jp/ncid/BA91570060" }