1980. Petition and Press Statement by Beuys et al, in protest against transferral of Boyle from Barlinnie Special Unit.
1973. Letter from Arnold Herstand to Richard Demarco. Ref. Twelve Hour Lecture blackboards by Joseph Beuys.
1973. Letter (page 1/2) from Demarco to Arnold Herstand, ref. Twelve Hour Lecture blackboards by Joseph Beuys.