@inbook {LadKor-DTBLEPVUAAT-2013,
	title = {Designing a technology based learning environment for place value using artifact-centric activity theory},
	booktitle = {Proceedings of the 37th conference of the International Group for the Psychology of Mathematics Education. Mathematics learning across the life span},
	volume = {1},
	year = {2013},
	pages = {188-192},
	keywords = {refereed},
	author = {Silke Ladel and Ulrich Kortenkamp},
	editor = {Anke M. Lindmeier and Aiso Heinze}
}
@conference {LibKor-RMDEA-2013,
	title = {The Role of Metadata in the Design of Educational Activities},
	booktitle = {Proceedings of CERME 8, Antalya},
	year = {2013},
	keywords = {refereed},
	author = {Paul Libbrecht and Ulrich Kortenkamp}
}
@conference {LibKorRebMul-TCTA-2013,
	title = {Tales of a Companion Teacher Analytics},
	booktitle = {Proceedings of the 2nd International Workshop on Teaching Analytics (IWTA-2013)},
	year = {2013},
	keywords = {refereed},
	url = {http://ceur-ws.org/Vol-985/paper4.pdf},
	author = {Paul Libbrecht and Ulrich Kortenkamp and Sandra Rebholz and Wolfgang M{\"u}ller},
	editor = {Ravi Vatrapu}
}
@conference {LibKorMer-IWIG-2009,
	title = {I2Geo: a Web-Library of Interactive Geometry},
	booktitle = {Proceedings of the 2nd Workshop Towards a Digital Mathematics Library (DML-2009)},
	year = {2009},
	publisher = {Masaryk University},
	organization = {Masaryk University},
	keywords = {refereed},
	isbn = {978-80-210-4781-5},
	author = {Paul Libbrecht and Ulrich Kortenkamp and Christian Mercat},
	editor = {Petr Sojka}
}
