1. AAAS (American Association for the Advancement of Science). (1990). Science for all Americans. New York: Oxford University Press.
2. Achinstein, P. (2001). The book of evidence. Oxford University Press.
3. Affolter, J. (2002). Provenance des silex préhistoriques du Jura et des régions limitrophes. Archéologie Neuchâteloise, 28(2).
4. Anderson, D., & Zhang, Z. (2003). Teacher perceptions of field-trip planning and implementation. Visitor Studies Today, 6(3), 6–11.
5. Boekaerts, M. (2006). Self-regulation and effort investment. In E. Sigel & K. A. Renninger (Eds.), Handbook of child psychology, Vol. 4 (pp. 345–377). Hoboken: John Wiley & Sons.