Musannaf Ibn Abi Shayba 1:71

Jarir narrated to us, from Yazid, who said: I saw Abd al-Rahman ibn Abi Layla perform ablution. He rinsed his mouth and inhaled water once or twice, and washed his face three times, and his forearms three times, and wiped his head, and washed his feet three times each. I did not see him comb his beard with his fingers. Then he said: "This is how I saw Ali perform ablution."