US patent 4427759, Gruetzmacher, Robert R. & Munger, Stanley H., "Process for preparing an overcoated photopolymer printing plate", issued 1984-January-24, assigned to E. I. Du Pont De Nemours And Company
US patent 4320188, Heinz, Gerhard; Richter, Peter & Jun, Mong-Jon, "Photopolymerizable compositions containing elastomers and photo-curable elements made therefrom", issued 1982-March-16, assigned to Basf Aktiengesellschaft