Sources

1) Source: Chancery: Inquisitions Post Mortem, Series I, Edward II "Alice de Veer alias de Ver, late countess of Oxford... The said Alice formerly gave the said manor to William de Warrene and Joan his wife, her daughter, in free marriage, to them and the heirs of their bodies, and they regranted it to her for life; the manor ought now to revert to John de Warenne their son and heir, aged 26."Dated: 9 Sep 1312. External Link
https://www.british-history.ac.uk/inquis-post-mortem/vol5/pp213-222. Reference: C 134/29/7 (Data from direct source)
2) Source: Special Collections: Ancient Petitions "People mentioned: Robert [de Vere], Earl of Oxford; Alice [de Vere, Countess of Oxford]; Henry III, King of England; Richard de Lovetoft, clerk; Bishop of Norwich; Edward I, King of England; William de Warenne; Joan [de Warenne], wife of William de Warenne; John de Warenne; Ivo de Audewincle; John de Warenne, son of John de Warenne; Alice [de Warenne], daughter of John de Warenne, senior, sister of John de Warenne, junior; Richard [FitzAlan], son of Alice de Warenne; Richard [FitzAlan], son of Richard FitzAlan, father of the petitioner; William Cokkyng, clerk; Richard II, King of England; Maurice Campeden; Payn Tiptot, knight; Peter Brauncher (Braunche)." Dated: c1402. External Link
https://discovery.nationalarchives.gov.uk/details/r/C9295233. Reference: SC 8/188/9355 (Data from secondary evidence)