Ordnance Survey Northern Ireland Quarter-inch Series.
Great Britain.Ordnance Survey.
Belfast : Ordnance Survey of Northern Ireland,
[1922-2005].
Relief shown by contour lines, spot heights.
refer to: C20(101-133).
refer to: 73-76, 100 (R. Hellyer: 1999).
includes: topographic, administrative, geological, scientific maps.
includes: 1:250,000, 1:253,440, 1:350,000, 1:500,000 scale maps.