Reference for “XML Schema Requirements”

@TechReport{Malhotra:99:XSR,
  author      = "Ashok Malhotra and Murray Maloney",
  title       = "{XML} Schema Requirements",
  month       = feb,
  note        = "http://www.w3.org/TR/1999/NOTE-xml-schema-req-19990215",
  year        = "1999",
  bibsource   = "http://w2.syronex.com/jmr/w3c-biblio",
  type        = "{W3C} Note",
  institution = "W3C",
}