Tesfamariam, G., A. Lykknes, and L. Kvittingen. “Small-Scale Chemistry for a Hands-on Approach to Chemistry Practical Work in Secondary Schools: Experiences from Ethiopia”. African Journal of Chemical Education, vol. 4, no. 3, June 2014, pp. 48-94, https://www.ajol.info/index.php/ajce/article/view/104097.