GSGS series 4228. Second Edition (Coloured). Italian Istituto Geografico Militare map dated 1937 and photolithographed by the British Ordnance Survey in 1943. Principal communications revised to 1940 using air photos. The meridians are based on the meridian of Rome, which is 12 degrees, 27 minutes and 7.1 seconds east of Greenwich. Contours at 10 metres interval. South Italy Grid "Blue".