Kusnandar, K., I. Junaedi, and A. Suyitno. “Analysis of Mathematical Connection Ability Based on Independent Character in Project Based Learning Assisted With Digital Module”. Unnes Journal of Mathematics Education Research, Vol. 10, no. 1, June 2021, pp. 35-39, https://journal.unnes.ac.id/sju/ujmer/article/view/43927.