protected static function resolveAssessmentSectionRef(AssessmentSectionRef $assessmentSectionRef, FileResolver $resolver)
    {
        try {
            $href = $resolver->resolve($assessmentSectionRef->getHref());

            $doc = new XmlDocument();
            $doc->load($href);
            $doc->xInclude();

            return $doc;
        } catch (XmlStorageException $e) {
            $msg = "An error occured while unreferencing section reference with identifier '" . $assessmentSectionRef->getIdentifier() . "'.";
            throw new XmlStorageException($msg, XmlStorageException::RESOLUTION, $e);
        }
    }