1. C. Crist, What do you need to know about the Delta variant, WebMD Health News, WebMD, LLC (2021)
2. A.Eu. Cha. Five months post-covid. Nicole Murphy’s heart rate is still doing strange things, The Washington Post, EST|Published (February 21, 2022)
3. R.W. DeBoer, J.M. Karemaker, J. Strakee, Hemodynamic fluctuations and baroreflex sensitivity in humans: a beat-to-beat model. Amer. J. Physiol. 253, 680–689 (1987)
4. R.Z. Sagdeev, D.A. Usikov, G.M. Zaslavsky, Nonlinear Physics: From the Pendulum to Turbulence and Chaos (Harwood Academic Publishers, New-York, 1988)
5. T.S. Krasnopolskaya, E.D. Pechuk, Chaos in a modified cardiorespiratory model. CMSIM 4, 563–570 (2013)