protected function checkNode(DOMNode $node, Tag $tag)
	{
		if ($node instanceof DOMAttr)
		{
			$this->checkAttributeNode($node, $tag);
		}
		elseif ($node instanceof DOMElement)
		{
			if ($node->namespaceURI === self::XMLNS_XSL && $node->localName === 'copy-of')
			{
				$this->checkCopyOfNode($node, $tag);
			}
			else
			{
				$this->checkElementNode($node, $tag);
			}
		}
	}