IQBAL, TASSAWAR, KLAUS HAMMERMÜLLER, and A MIN TJOA. 2011. “REALIZATION OF 3D VIRTUAL WORLD PLATFORM FOR THE BASIC EDUCATION OF ADULT ILLITERATES”. Journal of Mobile Multimedia 7 (3):194-215. https://journals.riverpublishers.com/index.php/JMM/article/view/4713.