[22] S. Mopoung, N. Sriprang and J. Namahoot, “Sintered filter materials with controlled porosity for water purification prepared from mixtures with optimal ratio of zeolite, bentonite, kaolinite, and charcoal”, Applied Clay Science, vol. 88-89, pp. 123-128, 2014. doi: http://dx.doi.org/10.1016/j.clay.2013.11.035