private function generateHead()
	{
		$out  = '<?xml version="1.0" encoding="utf-8"?>' . "\n";

		if ($this->version == self::RSS2)
		{
			$out .= '<rss version="2.0"
					xmlns:content="http://purl.org/rss/1.0/modules/content/"
					xmlns:wfw="http://wellformedweb.org/CommentAPI/"
				  >' . PHP_EOL;
		}
		elseif ($this->version == self::RSS1)
		{
			$out .= '<rdf:RDF
					 xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
					 xmlns="http://purl.org/rss/1.0/"
					 xmlns:dc="http://purl.org/dc/elements/1.1/"
					>' . PHP_EOL;
		}
		elseif ($this->version == self::ATOM)
		{
			$out .= '<feed xmlns="http://www.w3.org/2005/Atom">' . PHP_EOL;
		}
		return $out;
	}