Clwyd Powys Archaeological Trust

Gatehouse gazetteer of medieval fortifications

GENUK (St Harmon genealogy)

People’s Collection Wales

Rhayader Museum and CARAD

Royal Commission, Historical Monuments of Wales

Welsh Journals Online

Pencambria magazine

Historic Wales

History of Radnorshire

Radnorshire Society

Welsh Newspapers Online

Inventory of Ancient Monuments -Radnorshire
(Google Books, available as a PDF)
The Kilvert Society

Coflein

Abbeycwmhir Heritage Trust