Pasavant, P., P. Wongsuchoto, and V. Suksoir. “Mathematical Model for the Prediction of Gas-Liquid Mass Transfer in Airlift Contactors”. ASEAN Journal of Chemical Engineering, Vol. 5, no. 1, Dec. 2005, pp. 65-75, https://journal.ugm.ac.id/v3/AJChE/article/view/7636.