2Wang Z.Y.,et al.Effect of several new types compound fertilizers on quality of romaine lettuce from soil-less culture.Abstracts 12th World Fertilizer Congress,session 12:Fertilization and Food Quality.2001.197
3Stantamaria P.,Elia A.,Serio F.Fertilization strategies for lowering nitrate contents in leafy vegetables.Chicory and rochet salad cases.Journal of Plant Nutrition,1998,21(9):1791-1803