Musannaf Ibn Abi Shaybah 39082 — Judging by one witness and an oath

Ata and Ibn Abi Mulaykah narrate that the Messenger of Allah (peace and blessings be upon him) said: "Whoever sells a slave, the property of (that slave) belongs to the seller, unless the buyer stipulates it, (for example) by saying: 'I buy from you this slave and his property.'" It is mentioned that the view of (Imam) Abu Hanifah is: If the slave's property is more than the price, then it is not permissible.