Hammad bin Salama حماد بن سلمة · The Book of Manumission of Slaves

On the authority of his father: A man emancipated his share in a slave. The Prophet (ﷺ) did not put the responsibility on him to emancipate the rest. Ahmad said: The name Ibn al-Thalabb is to be pronounced with a ta' (and not with tha). As Shu'bah could not pronounce ta, he said tha.