@inbook { , title = {Challenges in End User Development in Intelligent Environments}, booktitle = {End User Development}, editor = {Lieberman, Patterno, Wulf.,}, year = {2006}, pages = {243-250}, publisher = {Springer Netherlands}, ISBN = {978-1-4020-5309-2}, author = {Ruyter de, B and Van de Sluis, R} }