Specified government bond interest tax exemption requires transferee to notify issuer within prescribed period for transfer. The Central Government specifies certain bonds issued by National Hydroelectric Power Corporation Limited as eligible under the proviso to the Income-tax Act governing tax deduction on interest, so that interest on those bonds is not subject to withholding; transfers by endorsement or delivery confer the benefit only if the transferee notifies the issuer by registered post within sixty days of the transfer.