@inproceedings{ kaschek_little_2004, title = {A little theory of abstraction.}, url = {http://cs.emis.de/LNI/Proceedings/Proceedings45/GI-Proceedings.45-6.pdf}, urldate = {2013-07-31}, booktitle = {Modellierung}, author = {Kaschek, Roland}, year = {2004}, pages = {75–92} }