public function belongsTo(NodeInterface $node)
	{
		parent::belongsTo($node);

		$rep = $this->sourceRepository;
		if ( ! ($rep instanceof RepositoryInterface)) {
			throw new Exception\WrongInstance($rep, 'RepositoryInterface');
		}
		$nestedSetRepository = $rep->getNestedSetRepository();
		/* @var $nestedSetRepository DoctrineRepository */
		
		$this->setRepository($nestedSetRepository);
		
		if ($this->right === null) {
			$nestedSetRepository->add($node);
		}
		$nestedSetRepository->register($node);
	}