@article{Formica04,
  title = {Legality of XML-Schema Type Hierarchies},
  author = {Anna Formica},
  year = {2004},
  url = {http://www3.oup.co.uk/computer_journal/hdb/Volume_47/Issue_05/470591.sgm.abs.html},
  tags = {XML, XML Schema},
  researchr = {https://researchr.org/publication/Formica04},
  cites = {0},
  citedby = {0},
  journal = {Comput. J.},
  volume = {47},
  number = {5},
  pages = {591-601},
}