subject approach to information / by A.C. Foskett Manual of visual signaling of the U.S. Signal Corps / prepared under the direction of brigadier-general A.W. Greely chief signal officer, U.S. Army by captain … Osinga en de interpretatie van Boyd / A.C. Tjepkema U.S.A.F. Unit Code Letters / by Roger A. Freeman and George Pennick heritage of the march Heritage of the March : Volume 55 - A.D. Davenport - A. Holzmann heritage of the march Heritage of the March : Volume 66 - L. Siede- A.F. Weldon