Musnad Ahmad 5:323

Ishaq ibn Ibrahim al-Razi narrated to us, Salama ibn al-Fadl narrated to us, Muhammad ibn Ishaq narrated to me, from Yazid ibn Abi Habib, from Marthad ibn Abdullah al-Yazani, from Abdullah ibn Zurayr al-Ghafiqi, from Ali ibn Abi Talib: "That the Messenger of Allah, peace and blessings of Allah be upon him, used to ride a donkey named 'Ufayr."