Ordnance survey Northern Ireland One-inch Series : Popular Outline.
Great Britain.Ordnance Survey.
Belfast : Ordnance Survey of Northern Ireland,
[1938-1953]
Relief shown by contour lines and spot heights.
Sheet 3. Londonderry and The Sperrins (1949) -- Sheet 5. West Tyrone (1950) -- Sheet 6. East Tyrone (1949) -- Sheet 7. Belfast (1953) -- Sheet 8. Fermanagh (1948) -- Sheet 9. Armagh (1948) -- Sheet 10. Mid-Down (1938) -- Sheet 11. The Mourne Mountains (1950).
refer to: C20(26-28), C20(41).
refer to: 30-31 (R. Hellyer: 1999).