public function pagesAffectedByChanges() {
    	$parent = $this->Parent();
    	$urls 	= array($this->Link());
		
		// add all parent (holders)
		while($parent && $parent->ParentID > -1 && $parent instanceof NewsHolder) {
    		$urls[] = $parent->Link();
    		$parent = $parent->Parent();
   		}
   		
   		$this->extend('updatePagesAffectedByChanges', $urls);
    	
    	return $urls;
  	}