Musannaf Ibn Abi Shayba 26:241

Ibn ‘Uyaynah narrated to us, from al-Zuhri, from Qabisah, who said: The grandmother—the mother of the mother or the mother of the father—came after the Messenger of Allah (may Allah bless him and grant him peace) to Abu Bakr and said: "My son’s son or my daughter’s son has died, and I have been informed that I have a right [to an inheritance]." Abu Bakr said: "I do not find for you any right in the Book of Allah, nor have I heard anything regarding you from the Messenger of Allah (may Allah bless him and grant him peace). I will ask the people." Al-Mughirah ibn Shu’bah testified that the Prophet (may Allah bless him and grant him peace) gave her one-sixth. He [Abu Bakr] said: "Who will testify with you?" He said: "Muhammad ibn Maslamah." So he testified, and he [Abu Bakr] gave her the one-sixth. The grandmother who was on the other side [the paternal grandmother] came to ‘Umar, and he gave her the one-sixth. He said: "If you both gather, it is between you." Ma’mar added: "And whichever of you is alone with it, it is for her."