@inproceedings{conf/iswc/KostylevCG14,
  title = "On the semantics of {SPARQL} queries with optional matching under entailment regimes",
  author = "Egor V. Kostylev and Bernardo {Cuenca Grau}",
  year = "2014",
  booktitle = "Proceedings of the 13th International Semantic Web Conference (ISWC 2014), Riva del Garda, Italy, October 19-23, 2014, Part {II}",
  pages = "374--389",
  publisher = "Springer",
  series = "Lecture Notes in Computer Science",
  volume = "8797",
}