def reference
            raise InvalidObjectError, "Cannot reference a direct object" unless self.indirect?

            ref = Reference.new(@no, @generation)
            ref.parent = self

            ref
        end
def reference
            raise InvalidObjectError, "Cannot reference a direct object" unless self.indirect?

            ref = Reference.new(@no, @generation)
            ref.parent = self

            ref
        end
Returns an indirect reference to this object.