From default Template:
        $this->cssIncludes[] = Template::parse('<link rel="stylesheet" href="{BOOTSTRAP_CDN}css/bootstrap-theme.min.css" crossorigin="anonymous">');
        $this->jsIncludes[] = Template::parse('<script language="JavaScript" crossorigin="anonymous" type="text/javascript" src="https://code.jquery.com/jquery-2.2.4.min.js"></script>');