AlSawalha, M. , Roessner, F. , Novikova, L. , Bel'chinskaya, L.. "Acidity of different Jordanian Clays characterized by TPD-NH3 and MBOH Conversion". World Academy of Science, Engineering and Technology, Open Science Index 55, International Journal of Chemical and Molecular Engineering (2011), 5(7), 584 - 588.