De Bittencourt, Valdomiro. "Complementary ion effect on K, Na and Ca release from bentonite and illite clay as affected from pH-dependent charge cation exchange capacity and base saturation /." Doctoral dissertation, Ohio State University, 1972. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486736094432709Chicago Manual of Style (17th edition)