function author($new = null, $return_entity = false)
    {
        if (isset($new)){
            if ($new instanceof Entity){
                $this->_author = $new;
                $new = $new->uri();
            }else{
                $this->_author = null; // for reloading
            }
            if ($new != $this->_attributes['author']){
                $this->change('author', $new);
            }
        }
        if ($return_entity){
            if (!isset($this->_author)){
                if (isset($this->_attributes['author'])){
                    $this->_author = Data::read($this->_attributes['author']);
                }else{
                    $this->_author = false;
                }
            }
            return $this->_author;
        }
        return $this->_attributes['author'];
    }