S.A. Strong, Reproductions in Facsimile of Drawings by the Old Masters in the Collection of the Earl of Pembroke and Montgomery at Wilton House, 1902, II, pl. 15 (as part of the Wilton sheet).
C. Pedretti and P. Trutty-Coohill, The Drawings of Leonardo da Vinci and his Circle in America, Florence, 1993, no. 30a.
M. Kwakkelstein, Leonardo da Vinci as a physiognomist: Theory and drawing practice, Leiden, 1994, pp. 107-8, note 223, fig. 57 (as part of the Wilton sheet).
C. Bambach, Leonardo da Vinci: Master Draughtsman, exhib. cat., New York, Metropolitan Museum of Art, 2003, p. 680, under no. 136.
F. Viatte and V. Forcione, Léonard de Vinci: Dessins et manuscrits, exhib. cat., Paris, Musée du Louvre, 2003, pp. 201, 204 and 220, under nos. 69, 70 and Folio 20 verso.