The Hortifroid symposium : Fifth International Symposium on Postharvest Physiology of Ornamental Plants : importance of cold in ornamental horticulture = Symposium Hortifroid : Cinquieme Symposium international sur la physiologie des plantes ornementals apres recolte : importance du froid en horticulture ornementale : Nice, France, March 11-15, 1991 - Hortifroid Symposium; Come, D. (International Society for Horticulture Science, 1991)