Letter from R. Magritte to A. Iolas, 8 August 1949.
Letter from R. Magritte to A. Iolas, 2 March 1950.
Letter from A. Iolas to R. Magritte, 7 April 1950.
Magritte, exh. cat., Hugo Gallery, New York, 1951, no. 8 (illustrated on the back cover; titled L'empire des lumières I).
H. Michaux, “En rêvant à partir de peintures énigmatiques” in Mercure de France, December 1964, pp. 593-594.
C. Bussy, “L’accent grave: Emission radiophonique” in Le fait accompli, nos. 19-20, April 1969.
Peintures de l'imaginaire: Symbolistes et Surrealistes belges, exh. cat. Galeries nationales du Grand Palais, Paris, 1972, p. 118.
J. Vovelle, “Peintres de l’imaginaire: Symbolistes et surrealists belges” in Cahiers d’histoire de l’art contemporain, no. 2, March 1973, p. 34.
D. Sylvester, ed., René Magritte: Catalogue Raisonné, Oil Paintings, Objects and Bronzes, 1949-1967, London, 1993, vol. III, pp. 4-5, 10, 17, 77, 145, 157, 162, 187, 200, 210, 222, 227, 228, 261, 368 and 387, no. 709 (illustrated in color, pp. 145 and 394).
S. Gohr, Magritte: Attempting the Impossible, New York, 2009, pp. 224-226 (illustrated in color, p. 225).