Xsd or vocabulary?

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#1

Deutsche Nationalbibliothek (German National Library) and hbz are working on a service1 which aims to facilitate the linking of data from different catalogues (whether library catalogues or union catalogues) by providing matching information about different records.

For this project we - amongst other things - need to link catalog entries to the bibliograhic identifiers in them. (There are a lot of identifiers in the realm of bibliographic data: widely known identifiers like ISBN, ISSN, DOI, URN, Handle, OCLC number, LCCN and many more local, regional and national identifiers. Some of them identify a bibliographic record while others identify the described bibliographic entity - which doesn't make it easier in a LOD context.)

The question here is how to represent a link in RDF from a record or a bibliographic resource to the associated identifiers. We have to decide between 1.) using individual predicates for each identifier or 2.) using the global predicate dc:identifier and characterizing the identifier more precisely through an xsd data type.

Here is an example for each approach:

1. The "predicate approach"

@prefix biro:  <http://purl.org/spar/biro/> .
@prefix cg:    <http://culturegraph.org/vocab/example/> .
@prefix dc:    <http://purl.org/dc/elements/1.1/> .

<http://opac.bib-bvb.de:8080/InfoGuideClient.fasttestsis/start.do?Query=-1="BV035542944>
  a biro:BibliographicRecord ;
  dc:source <http://lobid.org/collection/bvbcatalog> ;
  cg:bvn "BV035542944" ;
  cg:oclcn "991052625" ;
  ex:describes [
  cg:isbn "3-8273-2774-1"
  ] .
# ex:describes is because there is no inverse property to wdrs:describedby. 
# Does anybody know an appropriate predicate for this?

2. The "datatype approach"

@prefix biro:  <http://purl.org/spar/biro/> .
@prefix dc:   <http://purl.org/dc/elements/1.1/> .

<http://opac.bib-bvb.de:8080/InfoGuideClient.fasttestsis/start.do?Query=-1="BV035542944>
  a biro:BibliographicRecord ;
  dc:source <http://lobid.org/collection/bvbcatalog> ;
  dc:identifier "BV035542944"^^xsd:BVN ;
  dc:identifier "991052625"^^xsd:OCLCN ;
  ex:describes [
  dc:identifier "3-8273-2774-1"^^xsd:ISBN
  ] .

What do you think is the way to go: Creating an XSD or a vocabulary?

Adrian