Andrews P, Palm Kaplan K. PISA, TIMSS and Swedish students’ knowledge of linear equations: A ‘telling’ case of a system fixing something that may not be broken. AUPC [Internet]. 2020 Dec. 31 [cited 2024 Nov. 21];12:5-29. Available from: https://didacticammath.uken.krakow.pl/article/view/8417