Donza, A., R. Jones, R. Teixeira, and B. da Silva. “A Simple Electronic Circuit for an Automatic Train Safety Stop System”. Engineering, Technology & Applied Science Research 8, no. 4 (August 18, 2018): 3255–3259. Accessed April 7, 2025. https://mail.etasr.com/index.php/ETASR/article/view/2215.