Rare Proof print in orange-brown color of P. 1, 1 Rublis ND(1919), "Line Groups" watermark for P. 5a,b,c, G.D. Meijer tipografia Liepaja, Firma "Louis Staffel", with annotations of the printer, stamped on back side, light traces of former attachment on back side but crisp unfolded, condition: XF+ to aUNC.