Cutamora, Manuel. “Predictive Influence of Teacher Challenges and School Head Support on Teaching Effectiveness in Multigrade Classrooms in Lingig I District, Division of Surigao Del Sur: A Descriptive-Correlational Study”. International Journal of Education, Research, and Innovation Perspectives, vol. 2, no. 2, Feb. 2026, pp. 30-60, https://doi.org/10.5281/zenodo.18475572.