“VARIATION OF HEART RHYTHM OF ADOLESCENTS STUDYING AT SCHOOL IN THE SITUATION OF EXAMINATION”. Proceedings of the YSU B: Chemical and Biological Sciences 38, no. 2 (204) (April 30, 2004): 96–102. Accessed January 21, 2026. https://journals.ysu.am/index.php/proceedings-chem-biol/article/view/vol38_no2_2004_pp096-102.