S. A. S. Belal, E. O. Nazarenko, A. O. Radchenko, A. L. Kulik, A. V. Martynenko, and N. I. Yabluchansky, “IVABRADINE AND QUALITY OF BIOFEEDBACK IN THE LOOP OF PACED BREATHING UNDER THE CONTROL OF HEART RATE VARIABILITY PARAMETERS IN HEALTHY VOLUNTEERS”, J. V. N. Karazin Khark. Nat. Univ., Ser. Med., no. 25, pp. 13-16, Jul. 2015.