Christopher Lennox-Boyd; (Nicholas Stogdon, Oxford); purchased 2001 by NGA.
- Smith, John Chaloner. British mezzotinto portraits, being a descriptive catalogue of these engravings from the introduction of the art to the early part of the present century. 4 vols. London: Henry Sotheran and Co., 1884.
- Goodwin, Gordon. Thomas Watson, James Watson, Elizabeth Judkins. London, 1904.