P.Arunthathi, R.Keerthana, R.Kiruthika, M.Vennkatesan, and Gobalakrishnan. 2017. “Automatic Solar Powered College Bell System Using GSM”. International Journal of Intellectual Advancements and Research in Engineering Computations 5 (2):1238-40. https://doi.org/10.61096/ijiarec.v5.iss2.2017.1238-1240.