Musannaf Ibn Abi Shayba 18:72

Abu Bakr narrated to us, he said: Abd al-Rahim ibn Sulayman narrated to us, from Muhammad ibn Ishaq, from Makhul, and from Ash'ath, from al-Zuhri, that the Prophet, may God bless him and grant him peace, decreed regarding the slave woman [the payment of] one-third of the blood money.