Geraldine Winslow Goddard New York Genealogical and Biographical Society. Archibald Robertson, the Founder of the First School of Art in America. February 20, 1920, p. 1, calls the artist [her grandfather] a pupil and friend of Reynolds, and refers to this work as Robertson's "greatest miniature, which is believed to be the only miniature of Sir Joshua in existence, and [which] depicts the master in his scarlet cloak as Doctor of Laws".
Leo R. Schidlof. The Miniature in Europe in the 16th, 17th, 18, and 19th Centuries. Graz, Austria, 1964, vol. 2, p. 683.
Daphne Foskett. A Dictionary of British Miniature Painters. New York, 1972, vol. 1, p. 472.
Graham Reynolds with the assistance of Katharine Baetjer. European Miniatures in The Metropolitan Museum of Art. Exh. cat., The Metropolitan Museum of Art. New York, 1996, pp. 14, 145–46, no. 163, colorpl. 163 and ill. p. 145, date it between 1786 and 1791 and note that it is a copy after Reynolds's self-portrait of 1773 (Earl Spencer collection, Althorp).
Katharine Baetjer. "British Portraits in The Metropolitan Museum of Art." Metropolitan Museum of Art Bulletin 57 (Summer 1999), p. 64, ill. (color).