1. Kulik O.L., Schmidt O.J., Belal S.A.S., Rank I.A. IMPLEMENTATION OF BIOFEEDBACK IN A CLOSED LOOP OF HEART RATE VARIABILITY AND PACED BREATHING IN PATIENTS WITH ARTERIAL HYPERTENSION // The Journal of V. N. Karazin Kharkiv National University, series "Medicine". 2015. № 27. C. 10-15.