Ferreira Gullar. Konkrete Poesie, poesia concreta. Frauenfeld: Eugen Gomringer Press, 1965

“Gomringer also observed in contemporary usages of language a significant move toward fewer languages and global communication. The following assertion appeared in French and German in each issue of a series of booklets KONKRETE POESIE/POESIA CONCRETA published irregularly by Gomringer beginning 1960: la poésie concrète est le chapitre esthétique de la formulation linguistique universelle de notre epoque.
More and more, Gomringer observes, "thought structures . . . are decisive." The concrete poem which, as a construction of word materials contains thought, belongs to this trend. The conviction that the poem must remain within the sphere of word-sign communication permits it to play its role as a functional object. Language "even in its most primitive usage . . . serves a spiritual use,' Gomringer reminds us, 'so long as it is a language of words." Conceived in this context, the concrete poem fulfills Max Bill's requirement for concrete art: "production of the esthetic object for spiritual use".”

Mary Ellen Solt. Concrete poetry: a world view [online]. Bloomington: Indiana University Press, 1968