Erni Yudaningtyas, Achsanul Khabib, Waru Djuriatno, and Dionysius Joseph Djoko Herry Santjojo. 2020. “ELECTRET CONDENSER MICROPHONE AS SENSOR IN ARTERIAL PULSE RECORDING DEVICE”. GEOMATE Journal 19 (72):14-19. https://geomatejournal.com/geomate/article/view/1102.