Bluesman Sonny Grey poster on Craft Paper

Lithograph (31.5 X 44.5) sonny grey on craft paper, possibly poster studies. This is lithography and not offset reproduction. I put online (in the process) 3 other posters (or poster proposal) on different color supports, they can be associated for a very decorative set. Production of the 70s good state of conservation, traces of manipulations that for the most part will disappear once under glass.