- [S7] Plantagenet Ancestry: A Study in Colonial and Medieval Families (2004), Richardson, Douglas, edited by Kamball G. Everingham, (Baltimore: Genealogical Publishing Company, 2004), FHL book 942 D5rd., p. xxix (Reliability: 3).
- [S3] #21 The Complete Peerage of England, Scotland, Ireland, Great Britain and the United Kingdom, Extant, Extinct, or Dormant (1910), Cokayne, George Edward (main author) and Vicary Gibbs (added author), (New edition. 13 volumes in 14. London: St. Catherine Press,1910-), vol. 1 p. 28; vol. 2 p. 45 fn. (c), 73, 206; vol. 4 p. 207 (Reliability: 3).