Alali, Obadah, and Noor Aimie-Salleh. “Validation of Short-Term and Ultra-Short-Term Heart Rate Variability Measurement Based on Photoplethysmogram Using Commercial Mobile Application”. Journal of Medical Device Technology 3, no. 1 (June 30, 2024): 45–52. Accessed November 21, 2024. https://jmeditec.utm.my/index.php/jmeditec/article/view/54.