Resources found in the Smithsonian National Postal Museum Library are:
H.R. Hammer Ltd. London. “The Palace Collections of Egypt.” February 12 – 15, 17 – 18, 1954.
Lee, George L. Egypt – Royal Imperforate Printings. George L. Lee. Bernardsville, NJ. 1959. HE6185 E32L4X 1959.
Lee, George L. “The Special Royal Imperforate Printings of Egypt.” American Philatelist 71:12 (Sept 1958), 877 – 879. HE6187 A6X NPM
Lee, George L. “The Special Royal Imperforate Printings of Egypt.” The Air Post Journal 29:7 (April 1958), 194 -197. HE6187 A2987 NPM
Scott Catalogue Volume 2: Countries C-F. Sidney, OH.: Scott Publishing Company, 2009.
