EXAMINATION AND GRA~T OF PATENT 13. If on examination of an application, it is discovered tha t the formal requirements of rule 11 of these Rules have not been complied with, the Registrar shall rej ect the application. 14. Where the examination shows that the application satisfies the requirements of rules 8 and 11 of these Rules, the Registrar shall grant the patent. 15. Upon the grant of a patent, the Registrar shall issue to the applicant a document in Form 4 which shall bear the relevant number, the name and domicile of the patentee or his successor or assign if any, the dates of the patent application aI!d the grant, the ti tIe of the invention and the period of its validity, with reservations as to the rights of third parties, the number and date of the application on which a claim of foreign priority is based and the name of the foreign country concerned and where appropriate the name and address of the true inventor; a copy of the specification and a copy of the relevant drawings and plans, if any, shall be annexed to it. REGISTRATION AND PUBLICATION 16. As soon as may be, after the grant of a patent, the Registrar sha11(a) enter the particulars of the grant in the Register and this shall consist of the particulars named in rule 15 of these Rules; and (b) cause to be published in the Federal Gazette a notification of the grant containing the details mentioned in nile 15 of these Rules (except the description and the plans and drawings, if any) or a summary thereof if a summary form of notification is prescribed. DURATION OF PATENTS 17. Subject to regular payment of the annual fees due, patents shall be valid for twenty years from the date of the filing of the relevan t patent application.