Musannaf Ibn Abi Shayba 26:171

Waki’ narrated to us, he said: Sufyan narrated to us, from a man whom he did not name, who said: I have not seen a man who was more calculating than Ali. He was asked about two daughters, two parents, and a wife. He said: "Her eighth has become a ninth." Abu Bakr said: This is out of twenty-seven shares; for the two daughters sixteen, for the two parents eight, and for the wife three.