1958 Dec. 50/1 Le cinétisme de Tinguely retrouve la ‘couleur animée’ et l'International Klein's Blue (I.K.B.) y gagne un pouvoir d'incantation accru.]
1961 27 Jan. 58/1 Klein's favorite color is I.K.B. (International Klein Blue), which has something to do with the space age.
1990 (Nexis) 29 May 13 Elsewhere Kapoor coats a pair of massive, floored slabs of slate with pure pigment whose colour is unmistakably International Klein Blue.
2013 B. Wiseman in I. Strecker & M. Verne i. iii. 50 The whole point of International Klein Blue is that it connotes its own mechanical reproducibility.