Mersin, N. ., and E. N. Akkaş. “COMPARISON OF PROBLEMS RELATED TO THE MULTIPLICATION OF FRACTIONS IN MATHEMATICS TEXTBOOKS: THE CASE OF SINGAPORE AND TURKEY”. International Online Journal of Education and Teaching, vol. 9, no. 2, Mar. 2022, pp. 930-54, https://iojet.org/index.php/IOJET/article/view/1624.