- Avent R, CADW Guide to Criccieth Castle, Pennarth Fawr and St Cybi's Well, 1989, pp38-44;,
- Jones F, The Holy Wells of Wales, 1954, pp27, 74, 110-111 and 151;,
- RCHM Inventory of the Ancient and Historical Monuments in Caernarvonshire, II, 1960, item 1261, pp121-122, plate 80, and plan at fig 40;,