Grasshoppers 20 years; Royal Netherlands Airforce Helicopter Display Team 1993 Journal of the Royal Aeronautical Society : vol. XLIX Royal Air Force in the World War 1940-1945 volume III Royal Air Force in de oorlog Royal Air Force : yearbook 1993 Royal Flying Corps Right of the Line : The Royal Air Force in the European War 1939-1945 Royal Air Force : yearbook 1988 Royal Air Force Laarbruch Royal Australian Air Force, 1939-1942 / by Douglas Gillison Guns of the Royal Air Force 1939 - 1945 Royal Air Force
