1. Barrows, H. S., & Tamblyn, R M. (1980). Problem-based learning: An approach to medical education. Springer.
2. BattelleforKids. (2018). Portrait of a Graduate: A first step in transforming your school system. https://portraitofagraduate.org.
3. Boyles, E. T., & Mullen, C. A. (2020). Principals’ responsibility for helping impoverished students succeed in rural Appalachia. In C. A. Mullen (Ed.), Handbook of social justice interventions in education (pp. 1–27). Springer. https://doi.org/10.1007/978-3-030-29553-0_93-1.
4. Buck Institute for Education, The. (2018). PBL works. https://www.pblworks.org.
5. Colley, K. (2008). Project-based science instruction: A primer—An introduction and learning cycle for implementing project-based science. Science Teacher, 75(8), 23–28. https://eric.ed.gov/?id=EJ817851.