Gilbert Perlein & Bruno Corà (eds) & al., Yves Klein: Long Live the Immaterial! („An anthological retrospective“, catalog of an exhibition held in 2000), New York: Delano Greenidge, 2000, ISBN 978-0-929445-08-3, p. 226: „This symphony, 40 minutes in length (in fact 20 minutes followed by 20 minutes of silence) is constituted of a single 'sound' stretched out, deprived of its attack and end which creates a sensation of vertigo, whirling the sensibility outside time.“
