“Relationship Between Teacher Competence (Coach) and Improvement of Extracurricular Participants’ Singing Ability”. Avant-garde: Jurnal Ilmiah Pendidikan Seni Pertunjukan 2, no. 2 (November 9, 2023): 121–128. Accessed September 11, 2025. https://avant-garde.ppj.unp.ac.id/index.php/avant-garde/article/view/105.