1986–1990
Claudio Stickar, 1991
Gemini G.E.L., 1980
Gemini G.E.L., 1993
Gemini G.E.L., 1982
Daniel Freeman, 1972
Ken Price, 1992
Gemini G.E.L., 1969
Gemini G.E.L., 1972
Gemini G.E.L., 1989
Gemini G.E.L., 1971
![Drypoint Delta [special proof]](https://api.nga.gov/iiif/6467a0f7-a7ae-40fc-98b2-b27ea13e71b0/full/843,/0/default.jpg)
![Figure 5 [artist's proof]](https://api.nga.gov/iiif/ffa5b2b4-0959-412e-9c52-8dad680a1779/full/843,/0/default.jpg)
![Figure 6 [trial proof]](https://api.nga.gov/iiif/e1ed54ae-ef8b-4792-86e2-64e73a8b1d64/full/843,/0/default.jpg)