↑ 1.01.11.21.3 Cokayne, George Edward and HA Doubleday & Lord Howard de Walden eds. Complete Peerage of England, Scotland, Ireland, Great Britain and the United Kingdom, 2nd ed. London: St Catherine Press, 1936. Vol IX, pp 780-1.
See also:
Dallaway, J. (1830). "Pedigree of Mowbray." A history of the western division of the county of Sussex, Volume 2, Part 2, (pp.181). T. Bensley. Google Books.
Liddy, C.H. (2005). "The rise of the Grays of Heaton, c.1296 - 1415." North-east England in the Later Middle Ages. Boydell Press. [1]
Weis, F.L. (1999). The Magna Charta Sureties 1215, 5th ed.
Eleanor, born 1394, could not be the daughter of this John Nottingham with a date of death of 1382. The following source has John with the same birth date but dying before 12 Feb 1383 at the age of 17, unmarried.
https://en.wikipedia.org/wiki/John_de_Mowbray,_1st_Earl_of_Nottingham