Origins of pest, parasite, disease and weed problems: The 18th Symposium of the British Ecological Society, Bangor, 12-14 April 1976 / British Ecological Society - London: Blackwell Scientific Publication, 1977 - x, 413p. ISBN: 0-632-00226-3 Subjects--Topical Terms: Agriculture Subjects--Index Terms: Ecological Economics Universal Decimal Class. No.: 632 / L7