Oxford Dictionary of National Biography [ODNB]. From the earliest times to the year 2000. Vol. 1-60. Supplement 1 f. Matthew, Henry C. G. (ed.); Harrison, Brian. Oxford [u.a.] : Oxford University Press, 2004 ff.
Vol. 28, S. 468
Cokayne, George Edward: The complete peerage of England, Scotland, Ireland, Great Britain and the United Kingdom: extant, extinct or dormant. New edition, revised and much enlarged. London: St. Catherine Press, 1910-1959