public static function addTitle($text, $depth = 0) {
		$anchor = '_Toc'.++self::$_anchor;
		$bookmarkId = self::$_bookmarkId++;
		
		$title = array();
		$title['text'] = $text;
		$title['depth'] = $depth;
		$title['anchor'] = $anchor;
		$title['bookmarkId'] = $bookmarkId;
		
		self::$_titles[] = $title;
		
		return array($anchor, $bookmarkId);
	}