http://finregont.com/fro/xbrl/instance.ttl#EssentialNumericItemAttrs
Class 'instance:Essential numeric item attrs'

http://www.xbrl.org/2003/instance#essentialNumericItemAttrs

owl:Class

Attributes for all numeric items (fractional and non-fractional).

Essential numeric item attrs

instance:unit ref value exactly 1

instance:unit ref value only xsd:IDREF

instance:Item attrs