Matsyapurana 46.8

46.8

vasudevena sā dattā pāṇḍorbhāryā hy aninditā
pāṇḍorarthena sā jajñe devaputrān mahārathān //

After that Śûra, out of friendship, gave his daughter, Pṛithâ, for being adopted by Kuntibhoja, who was very old, and for that reason she also came to be known as Kuntî, the sister of Vasudeva. Vasudeva gave in marriage his sister, Kuntî, to King Pâṇḍu, for whom he bore several brave sons, through Devas.—7-8.