Yahya related to me from Malik from Yahya ibn Said that al-Qasimibn Muhammad said, "Two grandmothers came to Abu Bakr asSiddiq, and hewanted to give the sixth to the one who was from the mother's side,and a man of the Ansar said, 'What? Are you omitting the one from whomhe would inherit if she died while he was alive?' Abu Bakr divided thesixth between them.~
USC-MSA web (English) reference: Book 27, Hadith 5
Arabic reference: Book 27, Hadith 1081