Alen, John, A Cambridge Alumni Database, University of Cambridge
libraryireland.com
Webb, Alfred. "Archbishop John Allen", A Compendium of Irish Biography, M.H. Gill & Co., Dublin, 1878 Cite error: The named reference "Webb" was defined multiple times with different content (see the help page).
newadvent.org
Shahan, Thomas. "John Allen."The Catholic Encyclopedia. Vol. 1. New York: Robert Appleton Company, 1907. 22 Jan. 2015
James Gairdner in the DNB wrote "The archbishop knelt before [Lord Thomas] in his shirt and mantle, entreating for mercy. But the followers of Lord Thomas, mistaking, as some say, an order from their master, which was simply to take him away and put him in confinement, butchered him and most of his attendants without remorse" (Gairdner 1885, p. 306). Gairdner, James (1885). "Allen, John (1476-1534)" . Dictionary of National Biography. Vol. 1. pp. 305–307. ;