Tolong jelaskan mengenai Sumber dari Isabelle d'Angoulême

Fougère, Sophie. Isabelle d'Angoulême, Reine d'Angleterre, Edit-France, 1998.

Costain, Thomas B. The Conquering Family, Doubleday and Company, Inc., Graden City, New York, 1949, 1962

Costain, Thomas B. The Magnificent Century, Doubleday and Company, Inc., Garden City, New York, 1959

Cite bookTitleFour Queens: The Provençal Sisters who ruled EuropeLast nameGoldstoneFirst nameNancyPublisherViking PenguinYear of publication2007ISBN9780670038435Location of publicationNew YorkAuthors listGoldstoneCite bookTitleFour Queens: The Provençal Sisters who ruled EuropeLast nameGoldstoneFirst nameNancyPublisherViking PenguinYear of publication2007ISBN9780670038435Location of publicationNew YorkAuthors listGoldstone

Pertz Chronica ævi Suevici (Monumenta Germaniæ Historica, Scriptores 23) (1874): 874 (Chron. of Alberic de Trois-Fontaines: “… que domna Petro de Cortenaio, regis Philippi patruo, peperit comitem Petrum Comitem Autissiodorensem et Robertum de Cortenaio et quendam Guilelmum et sorores eorum. Una Alaydis comiti Guilelmo Ioviniaci peperit comitem Petrum, et post Engolismensi comiti peperit Isabellam modernam Anglie reginam …”).