See Peter Barturm, https://www.geni.com/documents/view?doc_id=6000000173427360005 (July 9, 2023; Anne Brannen, curator)

See Peter Bartrum, https://www.geni.com/documents/view?doc_id=6000000173396072829 (July 9, 2023; Anne Brannen, curator)

See Peter Bartrum, https://www.geni.com/documents/view?doc_id=6000000173395256873 (November 8, 2022; Anne Brannen, curator)

See Dwnn, Lewys, Heraldic Visitations of Wales and Part of the Marches, vol. 1, p. 324.

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