|SOME NOTES ON MEDIEVAL ENGLISH GENEALOGY|
Volume 2, pages 2, 3:
He [Ralph (Basset), Lord Basset of Drayton (d. 1342/3)] m. (settl. 27 Mar. 1304) Joan, da. of John DE GREY, [LORD GREY] of Wilton and Ruthin, by his 1st wife, Anne, da. of William DE FERRERS, of Groby, co. Leicester.
Joan appears to have been the daughter of John de Grey by his wife Maud, apparently the daughter of John de Verdun [see Grey (of Wilton or of Shirland), vol. 6, p. 174].