Gruffydd ab Iorwerth Foel

See Peter Bartrum, https://www.geni.com/documents/view?doc_id=6000000173392536995 (January 21, 2023; Anne Brannen, curator)

See Peter Bartrum, https://www.geni.com/documents/view?doc_id=6000000173393173917 (November 14, 2022; Anne Brannen, curator)

See Peter Bartrum, https://cadair.aber.ac.uk/dspace/bitstream/handle/2160/5120/bleddyn... (December 24, 2016; Anne Brannen, curator)

See Darrell Wolcott, "The Pedigree of Cynddelw Gam," http://www.ancientwalesstudies.org/id94.html for untangling and clarification of these lines. (February 29, 2016, Anne Brannen, curator)

Please see Darrell Wolcott: Pedigree of Cynddelw Gam of Ystrad Alun; http://www.ancientwalesstudies.org/id94.html; [#196] (Steven Ferry, November 28, 2017.)

Please see Darrell Wolcott: Owain Brogyntyn and His Family; http://www.ancientwalesstudies.org/id224.html. (Steven Ferry, January 8, 2019.)

Please see Darrell Wolcott: The Other "Sir Roger of Powys"; http://www.ancientwalesstudies.org/id56.html. (Steven Ferry, July 3, 2020.)

Please see Darrell Wolcott: The Ancestry of Owain Glyndwr; http://www.ancientwalesstudies.org/id200.html. (Steven Ferry, September 13, 2020.)

Please see Darrell Wolcott: Dating & Identifying Unfamiliar Welsh Families; http://www.ancientwalesstudies.org/id250.html. (Steven Ferry, December 2, 2020.)

Please see Darrell Wolcott: Women in Early Welsh Pedigrees; http://www.ancientwalesstudies.org/id251.html (Steven Ferry, January 1, 2021.)