Richardson, Douglas. Royal Ancestry: A Study in Colonial and Medieval Families, 5 vols, ed. Kimball G. Everingham. Salt Lake City: the author, 2013. See also WikiTree's source page for Royal Ancestry. Vol II, pg 57.
Camden Society Series (London, 1846) Vol. 35: "The Chronicle of Calais, in the Reigns of Henry VII and Henry VIII to the Year 1540" Page 46: 1536: "The words of ser Gorge Boleyne, brothar to qwene Anne, warden of the v. portes, on the xvij. of May, when he toke his deate at the Towre Hill at London, ..."
Find a Grave, database and images : accessed 29 December 2020), memorial page for George Boleyn (1502–17 May 1536), Find A Grave: Memorial #12380850, citing Chapel of Saint Peter-ad-Vincula, London Borough of Tower Hamlets, Greater London, England ; Maintained by Mark McManus (contributor 46593855) .