Authority

• urn:niso:z39.xx:lcsh:Duck
• urn:iso:132xxx:ITIS:TSN1234567

   Multiple Access Methods

• urn:niso:z39.xx:lcsh:Duck
  
• z39.50s://lcweb.loc.gov/
  
• http://ceres.ca.gov/LCSH?Duck
  
• ldap://subject.topics.org/

  Standardization

• Requirements
• Scope
• Version Control

Abstract Semantics

• Topic Maps
• RDF Schema