John Chaloner Smith British Mezzotinto Portraits...from the introduction of the art to the early part of the present century. Henry Sotheran & Company, vols. 1-4, 1878–83, vol. II, p. 520, no. 13.
Charles E. Russell English Mezzotinto Portraits and Their States. vol. II, London and New York, 1926, cat. no. 13 ii, p. 112.