Baldwin the Bald, Count of Flanders, from the book "The Genealogies and Old Forest Descents and the Counts of Flanders," by Corneille Martin, Pierre Balthasar, 1598. page 57.

Ancestry of Matilda de Flandre in The Royal Families of England, Scotland and Wales, pg. v-vii

Arnoul, Comte de Flandre, in Historie des Comtes de Flandre, pgs. 57 and 71

Arnoul, Comte de Flandre in Annales de Flodoard, pgs. xix introduction, 32 footnote 5, 46 footnote 10 and 70 footnote 1

Counts of Flanders in Ataviae Regiae, pg. 12

Baudoin II and Arnoul I, Counts of Flanders, in Chronique de Guines et D'Ardre, pgs. xxxi and xxxii introduction

Arnoul I, Count of Flanders, in Annales de Flandre, pgs. 152-153

Baudoin II, Count of Flanders, in Annales de Flandre, Vol. I, pgs. 137-140

Baudoin I and II and Arnoul, Counts of Flanders, in Les Origines de L'Ancienne France, pgs. 34-35 and footnote 4 and 39-40 and footnote 2

Baudoin I and II and Arnoul I and II de Flandre in Chronologie de la France Medievale, pgs. 33, 34, 35, 37, 38, 40, 41, 42 and 43

Baudoin I and II, Counts of Flanders, in Eudes, Comte de Paris et Roi de France, pgs. 99 and 222

Baudoin I and II, Counts of Flanders, in Bibliotheque de L'Ecole des Hautes Etudes, pgs. 99 and 222

Judith, Daughter of King Charles of France, in England's Queens, The Biography, pg. 19-21

Counts of Flanders in Burke's The Royal Families of England, Scotland and Wales, pgs. Part 1, v, vi and vii

Aethelwulf, King of Wessex, in Burke's The Royal Families of England, Scotland and Wales, pg. Part 1, x, xi, xii

Counts of Flanders in Matilda, Wife of the Conqueror, Queen of England, pgs. Introduction xvii, 1, 2 and 4