Musannaf Ibn Abi Shayba 26:483

Hafs narrated to us, from Ash'ath, from Jahm, from Ibrahim, regarding a woman who bought her father and then emancipated him, then he died and she had a sister. He said: "They both have two-thirds according to the Book of Allah, and she (the daughter who emancipated him) has the remaining third because she is his *'asabah* (residuary heir)." Abu Bakr said: "And it is the opinion held by me."