http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
from relations to semistructured data and XML
xiii, 257 pages : illustrations ; 25 cm.
Serge Abiteboul, Peter Buneman, Dan Suciu.
Includes bibliographical references (pages 241-248) and index.