Yusuf, M. 2018. Pengembangan Perangkat Pembelajaran IPA Berbasis Keterampilan Proses untuk Meningkatkan Keterampilan Berpikir Kritis Siswa SD: Development of Science Learning Tools Based on Process Skills to Improve Critical Thinking Skills for Elementary School Students. Pedagogia : Jurnal Pendidikan. 7, 1 (Feb. 2018), 32–46. DOI:https://doi.org/10.21070/pedagogia.v7i1.1303.