1. R.J. Rezba, C.R. Sprague, J.T. McDonnough and J.J. Matkins, Learning & Assessing Science Process Skills Fifth Edition. (Kendal/Hunt Publishing Company, Dubuque, 2007).
2. Kemendikbud, Permendikbud Nomor 66 tahun 2013 tentang Standar Penilaian Pendidikan (4 June 2013).
3. R.J. Marzano, The Art of Science Teaching (ASCD, Alexandria, 2007), p. 59.
4. Z. H. Ismail and I. Jusoh, Journal of Science and Mathematics Education in S.E Asia xxiv, 67–77 (2001).
5. A.C. Marasigan and A.A. Espinosa, International Journal of Learning, Teaching and Educational Research 1, 35–72, (2014).