MOHD FAUZI, Siti Yohana Akmal et al. Randomness Evaluation of Modified A5/1 Stream Cipher for Global System for Mobile Communication. Malaysian Journal of Science Health & Technology, [S.l.], oct. 2018. ISSN 2601-0003. Available at: <http://mjosht.usim.edu.my/index.php/mjosht/article/view/48>. Date accessed: 19 feb. 2019.