Fendri Martadinata, and Ridwan Hakim. “Use Of Certified Digital Signatures For Android-Based School Lettering”. Journal Health Applied Science and Technology 2, no. 2 (February 9, 2025): 168–172. Accessed March 26, 2026. https://jhast.ikestmp.ac.id/index.php/jhast/article/view/66.