Mesarius, G., and E. Surya. “Improve Learning Outcomes of Comparing Fractions by Using the Realistic Mathematical Learning Approach in Class Iii of Public Primary School 040457 of Berastagi”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 34, no. 1, June 2017, pp. 166-74, https://www.gssrr.org/index.php/JournalOfBasicAndApplied/article/view/7583.