GSGS series 4228. Second Edition (Coloured). Italian Istituto Geografico Militare map dated 1912 and photolithographed by the British Ordnance Survey in 1943. Revised in 1923. Principal communications revised to 1940 and area revised from 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 25 metres (V.I.). South Italy Grid "Blue".