Y. Qawqzeh, L. Kayed, M. Otoom, M. Alharbi, and F. A. Khan, “The Investigating of Photoplethysmogram Waveform Amplitude Changes: Aging and Atherosclerosis”, IJSBAR, vol. 30, no. 3, pp. 126–133, Nov. 2016, Accessed: Sep. 18, 2025. [Online]. Available: https://www.gssrr.org/JournalOfBasicAndApplied/article/view/6555