1-3. For Domestic Use, 1926. Laser printer forgeries: Arabian Philatelic Association letter to the Editor, OPAL,Whole Number 198 (November 1999): 54,55.
30, 44-48, 59-67, 86,87. 4b overprint hand-stamped on various issues, 1939-55. Forged surcharges: Carlson Chambliss, “Yemen’s 4-bogchah surcharges provide affordable collecting challenge”, Linn’s Stamp News (April 9, 2007): 28.