[S62] Kelley, David H. Genealogical Research in England: A New Consideration of the Carolingians, (Boston: The New England Historical and Genealogical Register volume CI, April 1947).
[S60] Stuart, Roderick W. Royalty for Commoners, The Complete Known Lineage of John of Gaunt, Son of Edward III, King of England, and Queen Philippa Fourth Edition, (Baltimore, Maryland: Genealogical Publishing Company, 2002).