Engeström, Y. (2015). Learning by expanding: an activity-theoretical approach to developmental research (2nd ed.). New York, N.Y: Cambridge University Press.

Giglio, M., & Perret-Clermont, A.-N. (2012). Prédire, agir et observer. Une méthodologie pour développer séquences pédagogiques et savoirs professionnels. Formation et Pratiques d’enseignement En Questions, (14), 127–140.

Heyning, L. (2011). “I Can’t Sing!” The Concept of Teacher Confidence in Singing  and the Use within their Classroom. International Journal of Education and the Arts, 12(13). Retrieved from http://www.ijea.org/v12n13/