G. Grappe, Catalogue du Musée Rodin, Paris, 1927, no. 143, p. 61 (the plaster illustrated).
H. Martinie, Auguste Rodin, 1840-1917, Paris, 1949, pl. 19 (the plaster illustrated).
A.E. Elsen, Rodin, New York, 1963, pp. 52-55 & 57.
I. Jianou & C. Goldscheider, Rodin, Paris, 1967, p. 88 (another cast referenced).
J. Tancock, The Sculpture of Auguste Rodin, Philadelphia, 1976, pp. 111-112, 114 & 116.
J. de Caso & P.B. Sanders, Rodin's Sculpture: A Critical Study of the Spreckels Collection, San Francisco, 1977, pp. 131 & 133-134. A.E. Elsen, ed., Rodin Rediscovered, Washington, 1981, pp. 66-67.
A.E. Elsen, The Gates of Hell by Auguste Rodin, Stanford, 1985, pp. 71 & 73-74.
A.E. Elsen, Rodin's Thinker and the Dilemmas of Modern Public Sculpture, New Haven & London, 1985, pp. 4, 7-8, 11-12, 17 & 48.
C. Lampert, Rodin: Sculpture and Drawings, London, 1986, p. 24 (another version illustrated p. 25).
K. Varnedoe, Rodin: A Magnificent Obsession, London, 2001, no. 73, pp. 96 & 175 (another cast illustrated pl. 73, p. 97).
A. Le Normand-Romain, The Bronzes of Rodin, Catalogue of Works in the Musée Rodin, vol. II, Paris, 2007, p. 587.