A. K.C. Huong, P. E. Ong, V. H. Tsen, and X. T. I. Ngu, “A Handheld Technology for Optical Monitoring of Transcutaneous Blood Oxygen Saturation”, IJET, vol. 7, no. 3.20, pp. 122–126, Sep. 2018, doi: 10.14419/ijet.v7i3.20.18994.