T. del Renzio, 'Arnaldo Pomodoro: Invention of a Sculptural Style', Art International, vol. XII, no. 6, Lugano summer 1968, pp. 96-98.
Ed. Mazzotta, Libro per le sculture di Arnaldo Pomodoro, Milan 1974, pp. 18-21 (illustrated).
S. Hunter, Arnaldo Pomodoro, New York 1982, pp. 78-79.
Exh. cat., Ohio, Columbus Museum of Art, Arnaldo Pomodoro, December 1983 - January 1984, no. 59 (another cast illustrated).
Ed. Il Cigno, Galileo Galilei, Arnaldo Pomodoro "Sphere within a Sphere", Roma 1997, p.86 (illustrated).
London, Marlborough New London Gallery, Arnaldo Pomodoro, July 1968, no. 2 (illustrated).
Rotterdam, Museum Boymans-van-Beuningen, Arnaldo Pomodoro, Rotterdam 1962, no. 7 (illustrated p.11).
Cologne, Kölnischer Kunstverein, Arnaldo Pomodoro Werke 1959-1969 , July-August 1969, no. 5.
Berkeley, University Art Museum, Arnaldo Pomodoro, Sculpture 1960-1970, May-July 1970, no. 10. This exhibition later travelled to San Diego, Fine Arts Gallery of San Diego, August-November 1970; Portland, Portland Art Museum, December 1970-January 1971; Austin Texas University Art Museum, February-March 1971 and Hartford, Wadsworth Atheneum, May-July 1971.
Florence, Forte di Belvedere, Luoghi fondamentali, sculture di Arnaldo Pomodoro, Florence July-October 1984, (illustrated pp. 100-101).