the Great Bear pamphlet series
This series of pamphlets, published by Something Else Press from 1965-67, featured experimental writing from the likes of John Cage, Allan Kaprow, Claes Oldenburg, and Nam Jun Paik. The pamphlets were anywhere from 16 to 32 pages in length, saddle-stitched, and printed on varying color stock; content included concrete poems, undoable acts, unactable plays, collages, essays, manifestos, and diaries.
you can download pdfs of the individual pamphlets HERE
you can buy reissued copies of the pamphlets HERE