L. R. Pino-Fan, D. I. Báez-Huaiquián, J. G. Molina-Cabero, and E. Hernández-Arredondo, “Criteria used by mathematics teachers to pose problems in the classroom”, Uniciencia, vol. 34, no. 2, pp. 114–136, Jul. 2020, doi: 10.15359/ru.34-2.7.