O. L. Kulik, O. J. Schmidt, S. A. S. Belal, і I. A. Rank, «IMPLEMENTATION OF BIOFEEDBACK IN A CLOSED LOOP OF HEART RATE VARIABILITY AND PACED BREATHING IN PATIENTS WITH ARTERIAL HYPERTENSION», J. V. N. Karazin Khark. Nat. Univ., Ser. Med., вип. 27, с. 10-15, Лип 2015.