Fritzsche L, Fritzsche M, Majoe D. Optimi (Online Predicative Tools For Intervention In Mental Illness). Biofeedback Based On Heart Rate Variability As A Preventive Tool Against Stress-Related Disorders. Psihìatr. nevrol. med. psihol. [Internet]. 2016Aug.25 [cited 2026Feb.1];2(2 (4):48–52. Available from: https://periodicals.karazin.ua/pnmp/article/view/6231