http://iflastandards.info/ns/unimarc/unimarcb/elements/5XX/hasDateOfExpressionExpressionInNamePreferredAccessPointIdentificationOfAnExpressionProvisionalTitleIsPrimaryEntryStructuredTitleStandardSubfieldsTechniqueInTitleIsPrimaryEntryStructuredTitleStandardSubfieldsTechniqueDateOfExpressionExpression.en