@booklet {958,
	title = {Mathematik mit digitalen Medien {\textendash} konkret. Ein Handbuch f{\"u}r Lehrpersonen der Primarstufe. 4. Band der Reihe Lernen, Lehren und Forschen mit digitalen Medien in der Primarstufe},
	year = {2018},
	publisher = {WTM-Verlag},
	address = {M{\"u}nster},
	author = {Ladel, Silke and Kortenkamp, Ulrich and Etzold, Heiko}
}
@inbook {805,
	title = {Artifact-Centric Activity Theory - A Framework for the Analysis of the Design and Use of Virtual Manipulatives},
	booktitle = {International Perspectives on Teaching and Learning Mathematics with Virtual Manipulatives},
	year = {2016},
	pages = {25-40},
	publisher = {Springer Verlag},
	organization = {Springer Verlag},
	address = {Heidelberg},
	author = {Ladel, Silke and Kortenkamp, Ulrich},
	editor = {Moyer-Packenham, Patricia}
}
@conference {764,
	title = {Development of a Flexible Understanding of Place Value},
	year = {2014},
	publisher = {A Mathematics Education Perspective on early Mathematics Learning between the Poles of Instruction and Construction (POEM)},
	organization = {A Mathematics Education Perspective on early Mathematics Learning between the Poles of Instruction and Construction (POEM)},
	address = {Malm{\"o}, Schweden},
	url = {http://www.mah.se/upload/FAKULTETER/LS/LS-seminarier/POEM/Ladel_Kortenkamp\%20-\%20Development\%20of\%20a\%20flexible\%20understanding\%20of\%20place\%20value.pdf},
	author = {Ladel, Silke and Kortenkamp, Ulrich}
}
@conference {765,
	title = {Flexible Use and Understanding of Place Value Via Traditional and Digital Tools. Research Report.},
	booktitle = {Proceedings of the 38th Conference of the International Group for the Psychology of Mathematics Education and the 36th Conference of the North American Chapter of the Psychology of Mathematics Education},
	year = {2014},
	publisher = {Psychology of Mathematics Education (PME)},
	organization = {Psychology of Mathematics Education (PME)},
	address = {Vancouver, Canada},
	author = {Kortenkamp, Ulrich and Ladel, Silke},
	editor = {Lilijedahl, Peter and Nicol, Cynthia and Oesterle, Susan and Allan, Darien}
}
@inbook {763,
	title = {Handlungsorientiert zu einem flexiblen Verst{\"a}ndnis von Stellenwerten - ein Ansatz aus Sicht der Artefact-Centric Activity Theory},
	booktitle = {Von Audiopodcast bis Zahlensinn},
	series = {Lernen, Lehren und Forschen mit digitalen Medien in der Primarstufe},
	volume = {2},
	year = {2014},
	pages = {151-177},
	publisher = {WTM-Verlag},
	organization = {WTM-Verlag},
	address = {M{\"u}nster},
	author = {Ladel, Silke and Kortenkamp, Ulrich},
	editor = {Ladel, Silke and Schreiber, Christof}
}
@inbook {762,
	title = {"Ist das dann noch ein Zehner oder ist das dann ein Einer?" - Zu einem flexiblen Verst{\"a}ndnis von Stellenwerten},
	booktitle = {Beitr{\"a}ge zum Mathematikunterricht 2014 - Beitr{\"a}ge zur 48. Jahrestagung der Gesellschaft f{\"u}r Didaktik der Mathematik vom 10. bis 14. M{\"a}rz 2014 in Koblenz},
	year = {2014},
	pages = {699-703},
	publisher = {WTM-Verlag},
	organization = {WTM-Verlag},
	address = {M{\"u}nster},
	author = {Ladel, Silke and Kortenkamp, Ulrich},
	editor = {Roth, J{\"u}rgen and Armes, Judith}
}
@article {731,
	title = {An activity-approach to multi-touch tools in early maths learning},
	journal = {The International Journal for Technology in Mathematics Education},
	volume = {20},
	year = {2013},
	pages = {3-8},
	author = {Kortenkamp, Ulrich and Ladel, Silke}
}
@article {757,
	title = {An activity-theoretic approach to multi-touch tools in early maths learning},
	journal = {The International Journal for Technoloy in Mathematics Education},
	volume = {20},
	year = {2013},
	pages = {3-8},
	author = {Ladel, Silke and Kortenkamp, Ulrich}
}
@conference {761,
	title = {Designing a technology based learning environment for place value using artefact-centric Activity Theory. Research Forum Activity Theoretical approaches to mathematics classroom practices with the use of technology},
	booktitle = {Proceedings of the 37th Conference of the International Group for the Psychology of Mathematics Education},
	year = {2013},
	publisher = {Psychology of Mathematics Education (PME)},
	organization = {Psychology of Mathematics Education (PME)},
	address = {Kiel, Germany},
	author = {Kortenkamp, Ulrich and Ladel, Silke},
	editor = {Lindmeier, Anke M. and Heinze, Aiso}
}
@book {758,
	title = {Early Mathematics Learning. Selected Papers of the POEM 2012 Conference.},
	year = {2013},
	publisher = {Springer},
	organization = {Springer},
	address = {New York},
	editor = {Kortenkamp, Ulrich and Brandt, Birgit and Benz, Christiane and Krummheuer, G{\"o}tz and Ladel, Silke and Vogel, Rose}
}
@inbook {760,
	title = {Number Concepts - Process of Internalization and Externalization by the Use of Multi-Touch Technology},
	booktitle = {Early Mathematics Learning. Selected Papers of the POEM 2012 Conference.},
	year = {2013},
	pages = {237-253},
	publisher = {Springer},
	organization = {Springer},
	address = {New York},
	author = {Ladel, Silke and Kortenkamp, Ulrich},
	editor = {Kortenkamp, Ulrich and Brandt, Birgit and Benz, Christiane and Krummheuer, G{\"o}tz and Ladel, Silke and Vogel, Rose}
}
@conference {754,
	title = {Finger-symbol-sets and multi-touch for a better understanding of numbers and operations},
	booktitle = {Proceedings of the Seventh Congress of the European Society for Research in Mathematics Education.},
	year = {2011},
	month = {Februar},
	publisher = {Congress of the European Society for Research in Mathematics Education (CERME)},
	organization = {Congress of the European Society for Research in Mathematics Education (CERME)},
	address = {Rzesz{\'o}w, Poland},
	author = {Ladel, Silke and Kortenkamp, Ulrich},
	editor = {Pytlak, Marta and Rowland, Tim and Swoboda, Ewa}
}
@conference {753,
	title = {Implementation of a multi-touch-environment supporting finger-symbol-sets},
	booktitle = {Proceedings of the Seventh Congress of the European Society for Research in Mathematics Education.},
	year = {2011},
	month = {Februar},
	publisher = {Congress of the European Society for Research in Mathematics Education (CERME)},
	organization = {Congress of the European Society for Research in Mathematics Education (CERME)},
	address = {Rzesz{\'o}w, Poland},
	author = {Ladel, Silke and Kortenkamp, Ulrich},
	editor = {Pytlak, Marta and Rowland, Tim and Swoboda, Ewa}
}
@conference {746,
	title = {Realisation of MERs (Multiple Extern Representations) and MERLs (Multiple Equivalent Linked Representations) in Elementary Mathematics Software},
	booktitle = {Proceedings of the Sixth Congress of the European Society for Research in Mathematics Education. January 28th - February 1st 2009, Lyon (France)},
	year = {2009},
	month = {Januar, Februar},
	publisher = {Congress of the European Society for Research in Mathematics Education (CERME)},
	organization = {Congress of the European Society for Research in Mathematics Education (CERME)},
	address = {Lyon, France},
	author = {Ladel, Silke and Kortenkamp, Ulrich},
	editor = {Durand-Guerrier, Viviane and Soury-Lavergne, Sophie and Arzarello, Ferdinando}
}
@article {743,
	title = {Virtuell-enaktives Arbeiten mit der "Kraft der F{\"u}nf"},
	journal = {MNU Primar},
	volume = {3},
	year = {2009},
	pages = {91-95},
	author = {Ladel, Silke and Kortenkamp, Ulrich}
}
