Musannaf Ibn Abi Shayba 26:467

Abu Bakr narrated to us, from Ibn Jurayj, who said: Some of the people of Sana'a informed me that Tawus gave a verdict regarding the inheritance of four people, one of whom testified that his father had claimed the lineage of a slave who was among them. Tawus did not permit his claim of lineage, but he gave the slave one-fifth of the inheritance from the wealth of the one who testified that his father had claimed him, and he emancipated the slave from the wealth of the one who testified.