public function addGuide($type, $href){
		if( !$this->dom->guide->count() ){
			$guide = $this->dom->addChild('guide');
		}else{
			$guide = $this->dom->guide;
		}
		$ref = $guide->addChild('reference');
		$ref['type'] = $type;
		$ref['href'] = $href;
		return $ref;
	}