...
- arxiv
- euclid
- ecommons / handles
- lsdi / handles
- digital collection registry: oai-pmh identifier
- purl resolver (for proxied and unproxied e-resources with urls in the cul catalog)
- voyager bib id
- voyager holdings id
- voyager item id
- voyager barcode no.
- worldcat local (e.g. http://cornell.worldcat.org/oclc/241827
where numeric is oclc no.)