@inproceedings{chekol-dbpl11,
    title = {{PSPARQL Query Containment}},
    author = {Chekol, Melisachew Wudage and Euzenat, J{\'e}r{\^o}me and Genev{\`e}s, Pierre and Laya{\"\i}da, Nabil},
    booktitle = {{DBPL 2011, Proceedings of the 13th International Symposium on Database Programming Languages}},
    pages = {8 pages},
    year = {2011},
    month = {Aug},
    pdf = {http://hal.archives-ouvertes.fr/hal-00619342/PDF/DBPL11.pdf}
}