Sources

1) Source: The Henry Project . External Link
https://fasg.org/projects/henryproject/data/aethe002.htm. Reference: Æthelred II "the Unready" (Questionable reliability of evidence)
2) Source: Ottonian Germany: The Chronicon of Thietmar of Merseburg "... the queen, still mourning the death of her husband and protector, as well as her sons, Aethelstan and Edmund...". Reference: Book 7, Chapter 40 (Data from secondary evidence)
3) Source: Chronica Magistri Rogeri de Houdene "After Aldred, his son Edmund Ironside reigned nearly nine months, during which he valiantly fought five battles against Canute, the king of the Danes." (Data from secondary evidence)
4) Source: Ottonian Germany: The Chronicon of Thietmar of Merseburg "In the year of the Incarnation, 1016, King Aethelred of the Angles died.". Reference: Book 7, Chapter 40 (Questionable reliability of evidence)
5) Source: The Henry Project . External Link
https://fasg.org/projects/henryproject/data/aelfg002.htm. Reference: Ælfgifu (?) (Unreliable evidence or estimated data)
6) Source: Ottonian Germany: The Chronicon of Thietmar of Merseburg "Because I have not already mentioned it, I will briefly explain who that Duke Otto was. The offspring of Duke Conrad and Luidgard, the daughter of Otto the Great". Reference: Book 5, Chapter 25 (Questionable reliability of evidence)
7) Source: The Henry Project . External Link
https://fasg.org/projects/henryproject/data/edmun002.htm. Reference: Eadmund "Ironside" (Questionable reliability of evidence)
8) Source: Chronica Magistri Rogeri de Houdene "Edmund Ironside before-named had a , Edward by name, who, shortly after the death of his father, through fear of king Canute, fled to the king of the Rugi, which we more properly call Russia; and the king of that country, Malesclotus by name, when he understood who he was, gave him an honourable reception. He there married a wife of noble birth, by whom he had Edgar Atheling, Margaret, afterwards queen of Scotland, and Christiana, her sister" (Data from secondary evidence)
9) Source: The Ecclesiastical History of England and Normandy: Volume III " Margaret was daughter of Edward exile of Hungary, who was son of Edmund, surnamed Ironsides, brother of Edward, king of England; the exiled Edward having married the daughter of Solomon, king of Hungary". Reference: 1093 (Data from secondary evidence)