Ancestry of Richard Plantagenet & Cecily de Neville @ chart 1398, d of Yves II de Beaumont Ct de Beaumont-sur-Oise, no mother
The cited information was published by published by author, 1978 (Ref: chart 1398, d of Yves II de Beaumont Ct de Beaumont-sur-Oise, no mother) The author/originator was Ernst-Friedrich Kraentzler.