1887
National Gallery of Art, 1837
National Gallery of Art, 1884
National Gallery of Art, 1995
National Gallery of Art, 1895
National Gallery of Art, 1647
National Gallery of Art, 1896
National Gallery of Art, 1975
National Gallery of Art, 1936
National Gallery of Art, 1920
National Gallery of Art, 1570
National Gallery of Art, 1498
National Gallery of Art, 2002
![Two Heads; Studies of Sheep [recto]](https://api.nga.gov/iiif/8268877b-c74c-46c7-85db-de619892d842/full/843,/0/default.jpg)
![Untitled (State Proofs and Proofs of Numbers) [state proof]](https://api.nga.gov/iiif/dc72fde6-7633-4935-a70f-b088683cecc2/full/843,/0/default.jpg)
