His piece “Sentences on Conceptual Art” is published in issue 5 of 0 to 9 magazine; it becomes one of the most widely cited artists' writings of the 1960s, exploring the relationship between art, practice and art criticism.
1968
A drawing for the opening of the Paula Cooper Gallery
He creates a work for the inaugural show of the Paula Cooper Gallery, an exhibition to benefit the Student Mobilization Committee to End the War in Vietnam; since then thousands of his drawings have been installed directly on walls.
27 juin 1968 – 6 octobre 1968
Exhibition: 4. documenta
1969
“When Attitude Becomes Form” in Bern
Harald Szeemann invites him to take part in “When Attitude Becomes Form” at the Kunsthalle Bern, Switzerland.
1970
First retrospective in The Hague
The Gemeentemuseum in The Hague presents his first retrospective exhibition.
1972–1973
Museum shows in Bern and Oxford
In 1972–1973 his exhibitions are mounted at the Kunsthalle Bern and the Museum of Modern Art, Oxford.
![Ginevra de' Benci [obverse], Leonardo da Vinci, c. 1474/1478](https://api.nga.gov/iiif/8f29e3c9-a289-4d53-abf0-31a66e9e98fa/full/!2400,2400/0/default.jpg)
![Wreath of Laurel, Palm, and Juniper with a Scroll inscribed Virtutem Forma Decorat [reverse], Leonardo da Vinci, c. 1474/1478](https://api.nga.gov/iiif/ff62e8d0-45c4-498f-ad36-6358de827e04/full/!2400,2400/0/default.jpg)
