Surya Putra, P., and N. Agus Purwanto. “The Leadership of School Principals in Improving the Quality of Vocational High Schools in Tanjung Selor District, Bulungan Regency”. Eduvest - Journal of Universal Studies, vol. 5, no. 7, July 2025, pp. 6443-6449., doi:10.59188/eduvest.v5i7.50389.