16 WRAPPING, DUPLICATING, COMPUTER, COPIER AND TYPEWRITER PAPERS, PRINTED PAPER FOR OFFICE USE, WRITING PAPERS AND ENVELOPES; SINGLE PLY AND CORRUGATED CARDBOARD BOXES, CARDBOARD FOR PACKAGING GOODS, PAPER PACKAGING MATERIALS; STATIONERY; BLANK PAPER TAPES AND CARDS, ALL FOR THE RECORDAL OF DATA; BOOKS, BOOKLETS, PAMPHLETS, CHARTS, MANUALS BROCHURES AND MAPS FOR INSTRUCTIONAL AND TEACHING PURPOSES PERTAINING TO THE POST OFFICE