public function uriSafe($spacer = "-")
  {
    $this->string = str_replace($spacer, " ", $this->string);
    $this->string = $this->transliterate();
		$this->string = preg_replace("/(\s|[^A-Za-z0-9\-])+/", $spacer, trim(strtolower($this->string)));
		$this->string = trim($this->string, $spacer);

		return new self($this->string);
  }