Gallardo, Jose, Giannina Bellone, and Marcelo Risk. “Ultra-Short Heart Rate Variability and Poincaré Plots”. ParadigmPlus 2, no. 3 (December 31, 2021): 37-52. Accessed January 22, 2022. https://journals.itiud.org/index.php/paradigmplus/article/view/25.