Muñoz Diosdado, A., G. Gálvez Coyt, and A. A. Martínez. “Thermodynamic Efficiency of the Cardiac Cycle and Irreversibility in the Interbeat Interval Time Series”. Revista Mexicana De Ingenieria Biomedica, vol. 31, no. 2, Feb. 2018, p. 8, https://rmib.mx/index.php/rmib/article/view/443.