@inproceedings {4955,
	title = {The Combined Approach to OBDA: Taming Role Hierarchies Using Filters},
	booktitle = {International Semantic Web Conference (ISWC)},
	year = {2013},
	doi = {10.1007/978-3-642-41335-3_20},
	author = {Carsten Lutz and Inan{\c c} Seylan and David Toman and Frank Wolter}
}
