@inproceedings{DL-12-Approx,
  title = "Efficient Upper Bound Computation of Query Answers in Expressive Description Logics",
  author = "Yujiao Zhou and Bernardo Cuenca Grau and Ian Horrocks",
  year = "2012",
  booktitle = "Proceedings of the 25th International Workshop on Description Logics (DL 2012)",
  location = "Rome, Italy",
  publisher = "CEUR",
}