J.P. Neale, Views of the Seats of Noblemen and Gentlemen in England and Wales, Scotland and Ireland, vol. 4, 1821, unpaginated (under Helmingham Hall); Ford 1951, pp. 36 and 62, pl. 70; WGC, pp. 88, 175, pl. 35b; Davies 1959, pp. 108-109; Parris 1973, p. 31; Herrmann 1973, p. 55, pl. 56; M. Rosenthal, British Landscape Painting, Oxford 1982, p. 64, fig. 52; Solkin 1982, pp. 207-9; J. Hayes, British Painting of the 16th-19th Centuries, Washington, 1992, pp. 334-36; R. White and J. Pike, 'Analyses of Paint Media', National Gallery Technical Bulletin, 1998, pp. 326-31; Egerton 1998, rev. 2000, pp. 326-31; S. Matthews, 'Manipulating the Landscape: Richard Wilson and the Dee Valley', Cheshire History, no. 40, Chester, 2000-2001, pp. 26-30