1968
National Gallery of Art, 1957
National Gallery of Art, 1993
National Gallery of Art, 1887
National Gallery of Art, 1955
National Gallery of Art, 1653
National Gallery of Art, 1997
National Gallery of Art, 1938
National Gallery of Art, 1985
National Gallery of Art, 1958
National Gallery of Art, 1550
National Gallery of Art, 1909
![Untitled [Serie Op. Oval]](https://api.nga.gov/iiif/ebd5c8ea-9bbc-4b19-ae1a-8048cf281e74/full/843,/0/default.jpg)
![Monkey Contemplating a Human Skull in a Landscape [reverse]](https://api.nga.gov/iiif/20e1c0d0-4eea-46d6-84d9-0e7b94fd0408/full/843,/0/default.jpg)