@book{23569,
	author = {Presmeg, Norma||Radford, Luis||Roth, Wolff-Michael||Kadunz, Gert},
	title = {Semiotics in Mathematics Education},
	url = {https://library.oapen.org/bitstream/20.500.12657/27970/1/1002029.pdf||https://library.oapen.org/bitstream/20.500.12657/27970/1/1002029.pdf||https://library.oapen.org/bitstream/20.500.12657/27970/1/1002029.pdf}
}