(1) Oliver Grau Virtual Art: From Illusion to Immersion, (Cambridge Massachusetts, MIT Press, 2003)
(2) Scott McCloud Understanding Comics (New York, HarperCollins, 1994), p. 43
(3) Oliver Grau, , p.13
(4) Shaleph O'Neill Interactive Media: The Semiotics of Embodied Interaction, p. 36
(5) Marshall McLuhan Understanding Media (Routledge 2001), p. 22
(6) Scott McCloud Understanding Comics (New York, HarperCollins, 1994), p. 63
(7) See http://csugrue.com/delicateBoundaries/
(8) See http://www.audiocommander.de/blog/?p=69