Theodore Rousseau Jr. "Reports of the Departments: Paintings." Metropolitan Museum of Art Bulletin 10 (Summer 1951), p. 30, as Hon. Charles Francis Greville.
Barry Maclean-Eltham. George Romney: Paintings in Public Collections. Kendal, England, 1996, p. 31, as Greville.
Ian Jenkins and Kim Sloan. Vases & Volcanoes: Sir William Hamilton and His Collection. Exh. cat., British Museum. London, 1996, p. 174, point out that the portrait on which Henry Meyer's 1810 mezzotint of Greville was based is not this one.
Katharine Baetjer. "British Portraits in The Metropolitan Museum of Art." Metropolitan Museum of Art Bulletin 57 (Summer 1999), pp. 47–48, ill. (color), explains that on the basis of comparison with the portrait of Greville by Romney which was engraved in mezzotint by Meyer in 1810, the sitter here cannot be he, and dates this portrait of an unidentified man about 1780.
Katharine Baetjer. British Paintings in The Metropolitan Museum of Art, 1575–1875. New York, 2009, pp. 126–28, no. 56, ill. (color).
Alex Kidson. George Romney: A Complete Catalogue of His Paintings. New Haven, 2015, vol. 1, p. 255; vol. 3, p. 719, no. 1569, ill. (color).