Chi Jung Kim and  Mincheol Whang and  Eui Chul Lee,  Identification of Arousal and Relaxation by using SVM-Based Fusion of PPG Features.   journal   = {International Journal of Psychological and Behavioral Sciences}, [online]. World Academy of Science, Engineering and Technology.
    November 2011, vol. 59(11). 588 - 592
    [viewed 20 September 2020]. Available from: https://publications.waset.org/pdf/10837.