Section 19
SEC. 19. The following articles may likewise be imported free of duty: (a) Paintings which are works of art, and have been exported with a custom-house certificate: Provided, That their identity is established to the satisfaction of the customs authorities. (b) Books, when, on their exportation, the number of the copies, the title of the work, and the name of the publisher have been stated in the export certificate. (c) Copper coins returned from foreign countries, if, on examination, it appears that they have been coined legitimately. (d) Articles returned from foreign exhibitions. (e) Articles of the Philippine Islands returned from foreign countries, the entry of which was prohibited at the place of destination.