K.C. Huong, Audrey, P E. Ong, V H. Tsen, and Xavier T. I. Ngu. “A Handheld Technology for Optical Monitoring of Transcutaneous Blood Oxygen Saturation”. International Journal of Engineering and Technology 7, no. 3.20 (September 1, 2018): 122–126. Accessed May 19, 2025. https://mail.sciencepubco.com/index.php/IJET/article/view/18994.