References for Constanza Infanta de Leon

---

W.K. v.Isenburg: Europäische Stammtafeln, Band II, Tafel 47. Marburg, 1953 (1965)
D.Schwennicke: Europäische Stammtafeln, Vol. II, Tafel 63. Marburg, 1984
S.de Vajay: From Alfonso VII to Alfonso X - The first two Centuries of the Burgundian Dynasty in Castile and Leon. 1989