TY  - CONF
TI  - Operationalization of the Metadata Element "Difficulty"
AF  - The Seventh IEEE International Conference on Advanced Learning Technologies
PP  - Los Alamitos, California - Washington - Tokyo
SN  - 978-0-7695-2916-5
PB  - IEEE Computer Society Press
SP  - 608
EP  - 612
PY  - 2007-07-01
AU  - Kastner, Margit 
AU  - Furtmüller, Gerhard 
ER -