Agutu, M. H., D. P. Gichohi, and D. B. Wamalwa. “Effects of Cooperative Thinking Skills Training Intervention on Academic Performance of Primary School Pupils in Nakuru West Sub-County, Kenya”. Journal of Education, vol. 2, no. 3, Sept. 2019, pp. 25-35, https://www.stratfordjournal.org/journals/index.php/journal-of-education/article/view/337.