Karam, F., R. Massaad, S. Skaf, J. Breidy, and Y. Rouphael. “Potato Response to Potassium Application Rates and Timing under Semi-Arid Conditions”. Advances in Horticultural Science, vol. 25, no. 4, May 2013, pp. 265-8, doi:10.13128/ahs-12761.