International patent classification / WIPO - Geneva: WIPO, 1994 - 7th ed. . Vol. 9 (Section B: Performing operations; transporting); ISBN: 92-805-0503-3; 352p. ISBN: 92-805-0503-3 Subjects--Topical Terms: Library science Subjects--Index Terms: Patent classification Universal Decimal Class. No.: D 025.4PATENt N4.2