| Mandatory | Repeatable | Editable |
|---|---|---|
| no | yes | yes |
This field contains identifiers from external systems other than the ISTC
Currently identifiers from the following external systems can be entered:
| Code | System | Displayed as |
|---|---|---|
| debsb | Bavarian State Library, Incunable Catalogue | BSB-Ink |
| degw | Gesamtkatalog der Wiegendrucke | GW |
| itigi | Indice Generale degli Incunaboli | IGI |
| itsbn | Catalogo del servizio bibliotecario nazionale | SBN(A) |
| ukhpb | CERL Heritage of the Printed Book Database | HPB |