public function getLicenseByIdentifier($identifier)
    {
        if (!isset($this->licenses[$identifier])) {
            return;
        }

        $license = $this->licenses[$identifier];

        // add URL for the license text (it's not included in the json)
        $license[2] = 'http://spdx.org/licenses/' . $identifier . '#licenseText';

        return $license;
    }