W[illiam]. Roberts. Sir William Beechey, R.A. London, 1907, p. 263, lists as number 67 of the 1786 Royal Academy exhibition "Portrait of an artist" by Beechey, then resident in Norwich [possibly this picture].
Basil S. Long. British Miniaturists. London, 1929, p. 297, notes that Beechey painted Miles's portrait.
Daphne Foskett. A Dictionary of British Miniature Painters. New York, 1972, vol. 1, p. 406, follows Long in noting that Beechey painted Miles.
Katharine Baetjer. "British Portraits in The Metropolitan Museum of Art." Metropolitan Museum of Art Bulletin 57 (Summer 1999), pp. 56–57, ill. (color), points out that the careers of Beechey and Miles followed a parallel course and that both lived for several years from 1782 at Market Place, Norwich, where the picture must have been painted; this sympathetic portrait suggests that the two were friends.
John Wilson in Oxford Dictionary of National Biography. 4, Oxford, 2004, p. 805, identifies it as one of fifteen small portraits by Beechey framed together in two frames, which were rejected by the Royal Academy in 1787 because Academy rules stated that all paintings had to be framed separately; adds that the pictures were subsequently exhibited in the gallery of the artist-dealer Benjamin Vandergucht.
Katharine Baetjer. British Paintings in The Metropolitan Museum of Art, 1575–1875. New York, 2009, pp. 152–53, no. 72, ill. (color).