Germano Celant, it can only be in "Supplement dedicated to Piero Manzoni", Turin 1967;
Piero Manzoni, published by Vanni Scheiwiller, Milano 1967, p. 56;
Germano Celant, Piero Manzoni, general catalog, Prearo Editore, Milan, 1975, p. 203, fig. FG;
Freddy Battino, Luca Palazzoli, Piero Manzoni, catalog raisonné, published by Vanni Scheiwiller, Milan, 1991, p. 465, n. 1050/9 BM;
Giorgio Verzotti, Lifelines, in "International Art Forum", New York, 1991, p. 177;
Gerald Silk, Mythhs and meanings in Manzoni's Merda d'Artista, "Art Journal", New York, 1993, p. 72, n. 8;
Hans Dickel, Die Sammlung Paul Maenz. Band 1. Objekte - Bilder - Installationen, Cantz, 1998, p. 40, n. 5;
Barbara Spahn, Piero Manzoni (1933-1963). Seine Herausforderung der Grenze von Kunst und Leben, Monaco, 1999. 12;
Germano Celant, Piero Manzoni. General Catalog, two volumes, published by Skira, Milan, 2004, pp. 498, 499, n. 683.