Martin, Cy. Men of the Twentieth. Manhattan Kansas, Aerospace Historian, 1974. Sm 4to (8.5x11"), 114 pages printed recto only, wrps, reprint of a typewritten manuscript by a crew chief in the 20th Aero Sqdn, WWI. Rather scarce WWI history of a famous 1st Day Bombardment Group released following a 20th Aero Sqdn reunion. G-VG.