British Kings and Queens @ p. 343
The cited information was published by 1998, Barnes and Nobles (Ref: p. 343) The author/originator was Mike Ashley.
References (3)
Parent Source:
British Kings and Queens
Individual:
Rhys Mechyll ap Rhys Gryg
Individual:
Lord Rhys Gryg ("the Hoarse") ap Rhys of Deheubert