Musannaf Ibn Abi Shayba 9:1141

Ibn al-Mubarak narrated to us, from Musa ibn Ayyub, who said: My paternal uncle, Iyas ibn Amir, narrated to me, saying: Ali said: Do not marry the woman whom your brother’s wife has breastfed, nor the woman whom your father’s wife has breastfed, nor the woman whom your son’s wife has breastfed.