Afriliandini, Farahnaz, dan Meida Nugrahalia. 2016. “The Implementation of Group Investigation Model on Learning Outcome at The Topic Ecosystem Class X In SMA Negeri 11 Medan Academic Year 2014 2015”. Jurnal Pelita Pendidikan 3 (4). https://doi.org/10.24114/jpp.v3i4.3989.