Pedaste, M., Palts, T., Kraav, T., & Orav-Puurand, K. (2021). Skills required to solve complex problems and their assessment and development in secondary school. Eesti Haridusteaduste Ajakiri. Estonian Journal of Education, 9(1), 138–161. https://doi.org/10.12697/eha.2021.9.1.06