Ordnance Survey England & Wales County of Brecknock.
Great Britain.Ordnance Survey.
Southampton : Ordnance Survey,
[1843-1960].
Relief shown by spot heights, hachures; 2nd & subsequent eds. with contour lines.
1st ed. (1843-1882); 2nd & subsequent eds. (1892-1960); Provisional ed. (1948-1965).
also titled 'Brecon'.
Llywodraeth Cymru Unitary Authority (Welsh Government 1996): Powys.
25" (1:2500) sheets: X.11 - XLV.11