1. Bellanca J. A. and Brandt R. S., 21st-century skills : rethinking how students learn. (Solution Tree Press, 2010)
2. PISA., Organisation for Economic Co-operation and Development., Source OECD (Online service), Assessing scientific, reading and mathematical literacy : a framework for PISA 2006. OECD, (2006)
3. Mastery of Science Concepts Improves Scientific Attitude in Elementary School Students
4. OECD, PISA 2015 Assessment and Analytical Framework science, reading, mathematic, financial literacy and collaborative problem solving (2017)