on verso, signed by artist? upper left in graphite: Parallel Stress. 1970; lower left stamped in black ink: © Dennis Oppenheim; center hand-written in red crayon: [?] 4
Eileen and Michael Cohen, New York; gift to NGA, 2011.
- Heiss, Alanna (with an essay by Thomas McEvilley). And the Mind Grew Fingers: Dennis Oppenheim, Selected Works 1967-90. New York, 1992.