Manalu, Ester, Saronom Silaban, Ramlan Silaban, and Wesly Hutabarat. 2016. “The Development of Chemical Practice Guidebook Colloid System-Based Integrated Contextual Character Values”. Jurnal Pendidikan Kimia 8 (2):87-89. https://doi.org/10.24114/jpkim.v8i2.4429.