Dr. Mustafa M. A-Faize, Worod M. Jabar, Hashim Sattar Shahd. “Effect of Surfactant on Hydrodynamic and Mass Transfer Charactersitics in Rotating Disc Contactor”. Design Engineering, Vol. 2021, no. 04, Apr. 2021, pp. 420 -34, http://thedesignengineering.com/index.php/DE/article/view/1376.