Books on G.B stamps and printers including the "Essential Guide to the G.B Line Engraved 1d and 2d Stars" by K.W Statham in 16 volumes, "May Dates" by M. Jackson, "De La Rue History of British & Foreign Postage Stamps" by J. Easton, "The De La Rue Years" by W. Wiseman, "Penny Red Stars" by G. Tonna, etc. (50+).