@inproceedings{Martin_and_Simpson_2003,
  title = "Generalizing the {Z} Schema Calculus: Database Schemas and Beyond",
  author = "Martin, A.~P. and Simpson, A.~C.",
  year = "2003",
  booktitle = "Proceedings of the 10th Asia-Pacific Software Engineering Conference ({APSEC 2003})",
  pages = "28--37",
  publisher = "IEEE",
}