Affiliation: | a A.G. Heyes is with the Department of Economics, Birkbeck College, University of London, 13–15, Greese Street, London W1P 1PA, UK b Catherine Liston-Heyes is with the Groupe de Recherche en Économie de l'Energie et des Ressources Naturelles, (GREEN), Université Laval, Quebec, G1K 7P4, Canada c National Westminster Centre for Management Studies, Royal Holloway and Bedford New College, University of London, Egham, Surrey, UK |