Saputro, Razis Aji, Risti Sokawati, Mudrikah Mudrikah, and Nikken Prima Puspita. 2017. “Classical Cryptography of Wind’s Eye Cell Circles”. Journal of Natural Sciences and Mathematics Research 2 (2):153-57. https://journal.walisongo.ac.id/index.php/JNSMR/article/view/1658.