Abu Ja'far Muhammad bin Ali bin al-Husayn said: I said to Sayyiduna Ka'b bin Ujrah (may Allah be pleased with him): Narrate what you heard from the Messenger of Allah (peace and blessings be upon him). He said: I heard him (peace and blessings be upon him) say: "The daughter of a brother and the daughter of a sister through breastfeeding are not lawful (in marriage)."
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16389