For example, the work W00508353600 has four instances, two of which only have the note "Julkaistu myös painettuna". These are in principle links to other instances, but with so little information that it's practically impossible to actually make the link. Thus they are useless and should be dropped from the output.
There are about 94k 530 notes. Of these, about 24k contain an ISBN. Maybe turning them (at least the ones without ISBN) into other types of notes (e.g. 500) would make sense.
For example, the work W00508353600 has four instances, two of which only have the note "Julkaistu myös painettuna". These are in principle links to other instances, but with so little information that it's practically impossible to actually make the link. Thus they are useless and should be dropped from the output.