lower center in plate: MUSICAL MONSTER. Publish'd Dec.r 8, 1778 by I Mortimer; by later hand, lower right in brown ink: J Mortimer
(William Weston Gallery, London, 28 February 1985); Donald Vogler, Portland, OR; gift to NGA, 2017.
- Sunderland, John. "John Hamilton Mortimer: His Life and Works," Walpole Society 52 (1986): no. 140.13