public function getCopiedFrom()
    {
        if (null === $this->_copiedFromTokenId) {
            $this->_copiedFromTokenId = $this->db->fetchOne(
                    "SELECT gtrp_id_token_old FROM gems__token_replacements WHERE gtrp_id_token_new = ?",
                    $this->_tokenId
                    );
        }

        return $this->_copiedFromTokenId;
    }