[LOWBROW ART]. WILLIAMS, Robert (b. 1943). Three Pieces of Exhibition Ephemera (one SIGNED by multiple artists). Circa 1980s. Includes: lower remnant of a ZAP 12 (1989) exhibition poster, with autographs of Robert Williams, Robert Crumb, Gilbert Shelton, Spain Rodriguez, Rick Griffin, S. Clay Wilson (partial). 12 ½ x 9 ½". Irregular trim with stain at left. — Psychedelic Solution / Limelight, Retroactive Retrospective, 1987. Exhibition poster featuring an image by Williams, “Dueling Bimbos (1986)". Double sided. 11 ½ x 13 ¼". Creases, folds, and edgewear. Tape remnants in corners verso; — Backdoor Bert (Model Sheet) by Robert Williams. Printed sheet on thin manila. 1970. Signed and dated in plate. 10 ¾ x 8 ½". Light random creases. Flat unframed. Good condition. All not backed.