M, Karthikeyan, Gowrishankar. KA, Rajith Sekar. G, E Elamaran, and B Sudhakar. “Multilevel Security System Using Raspberry Pi3”. International Journal of Engineering & Technology 7, no. 2.24 (April 25, 2018): 259–262. Accessed May 3, 2024. https://www.sciencepubco.com/index.php/ijet/article/view/12060.