Le Cote de Guermantes (The GuermantesWay) pt. 1 (1921). George Seldes, The Great Thoughts, quotes Ramon Guthrie: "This passage was meant to show what fools people who are capable of uttering such idiocies are... . It is slap-stick irony that Proust puts into the mouth of a fool (Boulbon) in order to show what a fool he was."
Interview in "Artforum" Magazine, November 1969; as quoted in "Six Years: The Dematerialization of the Art Object from 1966 to 1972" by Lucy R. Lippard, University of California Press, (p. 121), 1973.