Ndirangu, C. W. ., G. M. . Nyagah, and G. N. . Kimani. “The Level of Implementation of ASEI/PDSI Classroom Practices in Science Subjects: A Case of SMASSE Project, Kenya”. International Journal of Learning, Teaching and Educational Research, vol. 16, no. 5, May 2017, pp. 118-40, https://ijlter.net/index.php/ijlter/article/view/822.