Ingula, N., and N. Svyrydova. “Increased Sympathetic Tone of the Autonomic Nervous System As a Factor for Coronary Heart Disease”. East European Journal of Neurology, no. 3(15) (December 20, 2018): 32-35. Accessed March 2, 2021. https://neurology-jornal.org/index.php/journal/article/view/43.