Situmorang, J., & Hasairin, A. (2025). Analisis Kesulitan Belajar Siswa: Pendekatan Tes Diagnostik Berganda Dua Tingkat dan Kuesioner: (Analysis of Student Learning Difficulties: Two-Tier Multiple-Choice Diagnostic Test and A Questionnaire Approach). BIODIK, 11(02), 475–484. https://doi.org/10.22437/biodik.v11i02.43722