Khikmatun, L., S. Ngabekti, and E. Swarsi Rahayu. “Developing Learning Tools for Environmental Change Material Using Problem Based Learning Model Based on Local Environmental Conditions in Wonosobo”. Journal of Innovative Science Education, Vol. 9, no. 1, Apr. 2020, pp. 28 -39, doi:10.15294/jise.v8i1.32437.