(20) بَابُ: {وَأُمَّهَاتُكُمُ اللاَّتِي أَرْضَعْنَكُمْ}
Narrated Ibn `Abbas:
It was said to the Prophet, "Won't you marry the daughter of Hamza?" He said, "She is my foster niece (brother's daughter). "
Reference: Sahih al-Bukhari 5100
In-book reference: Book 67, Hadith 38
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 7, Book 62, Hadith 37