The Physicians of Myddvai: Meddygon Myddvai, or the medical Practice of the celebrated Rhiwallon and his Sons, of Myddvai, in Caermarthenshire, Physicians to Rhys Gryg, Lord of Dynevor and Ystrad Towy, about the Middle of the thirteenth Century - Pughe, J; Williams, J (Llanerch, 1993)