Sources

1) Source: Ottonian Germany: The Chronicon of Thietmar of Merseburg "He had the corpses of Margrave Gero... transported to Meissen... a tearful Count Herman took custody of the bodies... in the company of his brothers Gunther and Ekkehard... During the reign of Otto II, Archbishop Gero of Cologne and his brother, Margrave Thietmar, had founded an abbey there... Thietmar was Herman’sstepfather and the father of the dead margrave... Archbishop Gero commended the bodies to the earth and offered consolation to Gero’s lady, Adelheid, to his son, Thietmar". Reference: Book 7, Chapter 22 (Data from secondary evidence)
2) Source: Ottonian Germany: The Chronicon of Thietmar of Merseburg "Ekkehard, scion of the most noble lineage of eastern Thuringia... along with his father,Gunther... he joined himself in marriage to Swanhild, widow of Count Thietmar and Duke Bernhard’s sister. As their first-born child, she presented him with a daughter, named Liudgard". Reference: Book 4, Chapter 39
3) Source: Ottonian Germany: The Chronicon of Thietmar of Merseburg " Fourteen days later, on 26 November, Werner’s mother-in-law, the lady Swanhild, died suddenly.". Reference: Book 7, Chapter 7 (Data from secondary evidence)