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.
William Graham Sumner, (2013). “Folkways - A Study Of The Sociological Importance Of Usages, Manners, Customs, Mores And Morals”, p.251, Read Books Ltd