@inproceedings{Horrocks01a,
  title = "Enabling knowledge representation on the Web by Extending {RDF} Schema",
  author = "J. Broekstra and M. Klein and S. Decker and D. Fensel and F. van Harmelen and I. Horrocks",
  year = "2001",
  booktitle = "Proc.\ of the Tenth International World Wide Web Conference (WWW 2001)",
  isbn = "1-58113-348-0",
  month = "May",
  pages = "467--478",
  url = "download/2001/extending-RDF.pdf",
}