Sanders, I. J., English Baronies, A Study of Their Origin and Descent 1086-1327. Oxford: Clarendon Press, 1960. Information from this source tagged as [Ref: Sanders Baronies p[0-9]*].
Sources for birth and parent Information
brother:
Henry de UMFREVILLE of Devon [Ref: Sanders Baronies p49]
Research Notes:
inherited one fifth of the Barony of Great Torrington from brother [Ref:
Sanders Baronies p49]
transferred his share of the barony of Great Torrington to Gilbert II de
UMFREVILLE (d.1349), who in 1313 was pardoned for having thus obtained the
lands [Ref: Sanders Baronies p49]