Varga, J., K. Kardos, M.D. Ph.D., I. Nagy, M.D., F. Kudasz, M.D., & L. Szirtes, Dipl. Ing. Ph.D.. " Effect of Age and Life Characteristics on Variations of the Heart Rate Variability Parameters among Active Manual Workers." Medical Research Archives [Online], 9.10 (2021): n. pag. Web. 22 Dec. 2024