International patent classification / WIPO - Geneva: WIPO, 1999 - 7th ed. . Vol. 5 (Section E: Fixed constructions); ISBN: 92-805-0795-8; 79p. ISBN: 92-805-0795-8 Subjects--Topical Terms: Library science Subjects--Index Terms: Patent classification Universal Decimal Class. No.: D 025.4PATENt N9