| 01 | Proprietary | Note that <IDTypeName> is required with proprietary identifiers | 65 | |
| 91 | GND | Gemeinsame Normdatei – Joint Authority File in the German-speaking countries. See https://www.dnb.de/DE/Professionell/Standardisierung/GND/gnd_node.html (German) and https://www.dnb.de/EN/Professionell/Standardisierung/GND/gnd_node.html (English) | 66 | |
| B6 | FAST | Faceted Application of Subject Terminology, OCLC subject scheme derived from LCSH. See https://fast.oclc.org/fast/. Codes are up to 8 digits, for example 1430698 for the Booker Prize (see https://id.worldcat.org/fast/1430698) | 66 | |