Sarwari, A. Q., and M. N. A. Wahab. “The Effectiveness of HRV-Biofeedback Technology and Heart Rate Variability on Intercultural Communication Competence Among Postgraduate Students from Different Nationalities”. The International Journal of Humanities & Social Studies, vol. 5, no. 10, Oct. 2017, https://internationaljournalcorner.com/index.php/theijhss/article/view/125575.