Sadkhan, Sattar B., and Nibras Hadi Jawad. “Improvement of A5/1 Encryption Algorithm Based on Using Unit Delay”. Al-Qadisiyah Journal of Pure Science 19, no. 3 (July 19, 2017): 211-222. Accessed May 4, 2024. https://journalsc.qu.edu.iq/index.php/JOPS/article/view/157.