Cf. Kaggelaris, N. - Koutsioumari, M. I. (2015), "The breaktime as part of the hidden curriculum in Public High School", Pedagogy theory & praxis 8 (2015): 76-87 [1].
Margolis, Eric, Michael Soldatenko, Sandra Acker, and Marina Gair. "Peekaboo: Hiding and Outing the Curriculum." The Hidden Curriculum in Higher Education. Ed. Margolis, Eric. New York: Routledge, 2001.