ヴォルスンガ・サガ
According to the Edda and "Völsunga saga", Hamdir and Sörli were the sons of Gjuki's daughter Guðrún and King Jonakr. Erpr was the son of Jonakr from an earlier marriage. Svanhildr, the daughter of Sigurðr and Guðrún, was also raised by Jonakr.