Adelia, Windah Sari, and Edy Surya. “Resolution to Increase Capacity by Using Math Students Learning Guided Discovery Learning (gdl)”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 34, no. 1, June 2017, pp. 144-5, https://gssrr.org/JournalOfBasicAndApplied/article/view/7521.