Widiawati, Rida, et al. “Learning Challenge: Solar Cell Technology in PjBL- STEM Learning Using Jigsaw Strategy to Enhance the 21st Century Skills of 9th Graders”. Jurnal Penelitian Pendidikan IPA, vol. 9, no. 10, Oct. 2023, pp. 8846-51, doi:10.29303/jppipa.v9i10.5126.