S. Hussain, “Improvement of Drought Tolerance in Sunflower (Helianthus annuus L.) By Foliar Application of Abscisic Acid and Potassium Chloride”, Pak. J. Nutr., vol. 12, no. 4, pp. 345–352, Mar. 2013, doi: 10.3923/pjn.2013.345.352.