Macapañas, Ponciano, and Emilio Albos. “Signal and Intercommunication System Trainer: A Technical Study”. SSU - Digital Archive for Theses and Dissertations 10, no. 1 (August 12, 2022): 1–116. Accessed November 24, 2024. https://datd.ssu.edu.ph/index.php/datd/article/view/180.