public function importAuxiliaryFiles(QtiResource $qtiItemResource)
    {
        $qtiFile = $this->getSource() . \helpers_File::urlToPath($qtiItemResource->getFile());
        foreach ($qtiItemResource->getAuxiliaryFiles() as $auxiliaryFile) {
            $absolutePath = $this->getAbsolutePath($auxiliaryFile);
            $relativePath = $this->getRelativePath($qtiFile, $absolutePath);

            if (!\helpers_File::isFileInsideDirectory($relativePath, dirname($qtiFile))) {
                throw new InvalidSourcePathException(dirname($qtiFile), $auxiliaryFile);
            }

            try {
                $this->importAsset($absolutePath, $relativePath);
            } catch(\common_Exception $e) {
                throw new AssetManagerException(
                    'Error occurs during auxiliary assets handling for item: ' . $qtiItemResource->getIdentifier()
                    . ', assetFile: ' . $relativePath,
                    0, $e
                );
            }
        }
        return $this;
    }