lower center in plate: SLEEPING MONSTERS. / Published as the Act directs Jan. 25, 1780 by J. Mortimer, Norfolk Street, Strand; lower right in plate: I. Mortimer Del et Sculp.
(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 (1988): no. 184a.