All 13 digit EANs with the 979 prefix are validating as ISBNs (ISBNValidator). There are 2 issues with this.
- 979-0 prefixed numbers are allocated to the ISMN agency and represent music works. https://www.ismn-international.org/whatis.html
- 979-[2-9] are unassigned at present, that is they have not yet been allocated to a country agency (or another authority).
see attached xml (from www.isbn-international.org/export_rangemessage.xml RangeMessage.xml ) for the current valid ranges for ISBN
An example unassigned 'ISBN' is 9792222222223