Message
ISNI identifier "." should have attribute institution-id-type="isni"
Rule XPath:
This rule ASSERTS the following, raising an alert if FALSE:
not(matches(., '[0]{4}[\p{P}\p{Z}]*[0-9]{4}[\p{P}\p{Z}]*[0-9]{4}[\p{P}\p{Z}]*[0-9]{3}[0-9Xx]'))
or (@institution-id-type = 'isni')