Edward Hamilton. The Engraved Works, of Sir Joshua Reynolds: A Catalogue Raisonné of the Engravings Made after His Paintings from 1755–1822. 2nd ed. (1st ed., London, 1874; repr., Amsterdam, 1973). London, 1884, pp. 5, 164, states that John Barker sat in 1786–87 and supplies biographical details; notes that the portrait had belonged to Sir Thomas Lawrence and records the buyer at the Lawrence sale as Mrs. Carker, for 32 guineas.
Algernon Graves and William Vine Cronin. A History of the Works of Sir Joshua Reynolds P.R.A. 1, London, 1899, p. 51, note a payment of £210 on April 7, 1786, for "Mr. Barker and Fa—"; quote three contemporary comments on the portrait, and record the buyer at the Lawrence sale as Gilmore, for £65.2.0.
Walter Armstrong. Sir Joshua Reynolds, First President of the Royal Academy. London, 1900, p. 192.
A. L. Baldry. Sir Joshua Reynolds. London, , p. xxxviii.
James B. Townsend and W. Stanton Howard. Memorial Catalogue of Paintings By Old and Modern Masters Collected by Edward R. Bacon. New York, 1919, p. 47, no. 54.
Ellis K. Waterhouse. Reynolds. London, 1941, pp. 78, 84.
David Mannings and Martin Postle. Sir Joshua Reynolds: A Complete Catalogue of His Paintings (The Subject Pictures catalogued by Martin Postle). New Haven, 2000, vol. 1, p. 73, no. 108; vol. 2, fig. 1475, lists seven appointments with the sitter (February 15, 17, 23, and 24, March 9 and 17, and April 7) and a payment of 2000 guineas on April 7, 1787; points out discrepancies in the listings of the size of the canvas, which must have been cut down.
John H. Appleby. "Joshua Reynolds's Portrait of John Barker, Chairman of Ramsgate Harbour." Metropolitan Museum Journal 41 (2006), pp. 133–39, fig. 1, provides extensive biographical details on the sitter, especially concerning his involvement in the construction of Ramsgate Harbor.
Katharine Baetjer. British Paintings in The Metropolitan Museum of Art, 1575–1875. New York, 2009, pp. 78–80, no. 33, ill. (color).
Giovanna Perini in Federico Barocci, 1535–1612: l'incanto del colore, una lezione per due secoli. Exh. cat., Santa Maria della Scala, Siena. Cinisello Balsamo, Milan, 2009, pp. 246, 248–49 n. 45, fig. 177 (color), suggests that the composition is based on Barocci's portrait of Giuliano Della Rovera (ca. 1595; Kunsthistorisches Museum, Vienna).