1. Department of Soil Science and Plant Nutrition, Cukurova University, in Adana, Turkey.
2. Weizmann Institute of Science in Rehovat, Israel.
3. International Center for Maize and Wheat Improvement (CIMMYT) in Ankara, Turkey.
4. US Department of Agriculture-Agricultural Research Service (USDA-ARS), US Plant Soil and Nutrition Laboratory, at Cornell University in Ithaca, New York, USA.
5. University of Hohenheim, Institute of Plant Nutrition, in Stuttgart, Germany.