BelalS. А. S., A. L. Kulik, A. V. Martynenko, and M. I. Yabluchanskiy, “BIOFEEDBACK QUALITY IN THE LOOP OF PACED BREATHING AND HEART RATE VARIABILITY PARAMETERS IN HEALTHY VOLUNTEERS OF DIFFERENT RACE”, J. V. N. Karazin Khark. Nat. Univ., Ser. Med., no. 24, pp. 13-17, 1.