Marcel Brion, Paul Klee, Paris, 1955, no. 12, illustrated (titled Pierre Commémorative pour N. )
Carola Müller, Das Zeichen in Bild und Theorie bei Paul Klee, Ph.D. dissertation, Technische Universität München, Munich, 1979, p. 48
Wolfgang Kersten and Osamu Okuda, Paul Klee , Stuttgart, 1995, fig. 15, p. 62, illustrated
Jenny Anger, Modernism and the Gendering of Paul Klee , Ph.D. dissertation, Brown University, Providence, 1997, p. 109 (titled Memorial to N )
Josef Helfenstein and Christian Rümelin, eds., Paul Klee: Catalogue Raisonné , vol. II, London and New York, 2000, no. 1927, p. 485, illustrated; p. 472, illustrated in color
Exh. Cat., Kyoto, National Museum of Modern Art and Tokyo, National Museum of Modern Art, Paul Klee: Art in the Making 1883-1940, 2011, p. 86, illustrated
Brigitte Uhde-Stahl, Paul Klees geheime Symbolik , Berlin, 2018, pp. 196, 219, 283, 294; p. 244, illustrated in color