Thang, N. T.; Phuong, N. T.; Hanh, P. K.; Lan, N. M.; Quynh, N. P.; Phuong, P. T. M.; Ly, D. T.; Ngan, D. T. H. HAPPINESS INDICATOR OF STUDENTS OF VNU UNIVERSITY OF LANGUAGES AND INTERNATIONAL STUDIES DURING COVID-19 PANDEMIC LOCKDOWN IN HANOI, VIETNAM. JFS 2022, 38, 76-86.