Purwaningsih, K., Z. Zaenuri, and I. Hidayah. “Analysis of Concept Understanding Ability in Contextual Teaching And Learning in Quadrilateral Materials Viewed from Students Personality Type”. Unnes Journal of Mathematics Education, Vol. 6, no. 1, Mar. 2017, pp. 142 -51, doi:10.15294/ujme.v6i1.12642.