1. Andersson, B. & Kärrqvist, C. (1983). How Swedish pupils, aged 12–15 years, understand light and its properties. International Journal of Science Education, 5(4), 387–402.
2. Blumör, R. (1993). Schülerverständnisse und Lernprozesse in der elementaren Optik: Ein Beitrag zur Didaktik des naturwissenschaftlichen Unterrichts in der Grundschule. Magdeburg: Westarp Wissenschaften.
3. Chauvet, F. (1996). Teaching colour: designing and evaluation of a sequence. European Journal of Teacher Education, 19(2), 121–136.
4. Chen, C., Lin, H. & Lin, M. (2002). Developing a Two-Tier Diagnostic Instrument to Assess High School Students’ Understanding-The Formation of Images by a Plane Mirror. Proceedings – National Science Council Republic of China Part D Mathematics Science and Technology Education, 12(3), 106–121.
5. Chu, H., Treagust, D. & Chandrasegaran, A. L. (2009). A stratified study of students’ understanding of basic optics concepts in different contexts using two-tier multiple-choice items. Research in Science and Technological Education, 27, 253–265.