SAJKA, M., ROSIEK, R., BŁASIAK, W., ANDRZEJEWSKA, M., GODLEWSKA, M., KAZUBOWSKI, P., ROŻEK, B., STOLIŃSKA, A. and WCISŁO, D. 2015. Pupil Size Reactions of Middle School Students during the Process of Solving a Problem – a Comparative Analysis. Journal of Education, Technology and Computer Science. 13, 3 (Sep. 2015), 188–194.