Interfunktionen, periodical, black-and-white, various sized volumes, 10 volumes, published by Heubach, Cologne. 
Interfunktionen was started by Friedrich (Fritz) Heubach after a march in 1968 on the occasion of Documenta, when Joseph Beuys, Wolf Vostell and others went to protest the closedness of the exhibition. Heubach was inspired by Vostell’s magazine Decollage. More interesting anekdotes here. Thanks to Specific Object / David Platzker for the images.