M. P. Assalim T P, D. Titisari, W. Caesarendra, and B. A. Prakoso, “Analysis of the Effect of Red LED and Infrared Flip Flop Frequency on SpO2 Measurement Accuracy”, Indones.J.electronic.electromed.med.inf, vol. 4, no. 2, pp. 62-67, May 2022.