WASET
    Liping Li and  Ke Li and  Changchun Liu and  Chengyu Liu and  Yuanyang Li,  A New Method in Short-Term Heart Rate Variability — Five-Class Density Histogram.   journal   = {International Journal of Biomedical and Biological Engineering}, [online]. World Academy of Science, Engineering and Technology.
    September 2011, vol. 57(9). 394 - 397
    [viewed 16 April 2024]. Available from: https://publications.waset.org/pdf/160.