Musnad Abu Ya'la al-Mawsili 118:50

Muhammad ibn Yahya ibn Abi Samina al-Baghdadi narrated to us, Abd al-A’la ibn Abd al-A’la narrated to us, from Ma’mar, from al-Zuhri, from Anas ibn Malik, who said: Al-Hasan ibn Ali was the most similar of them in face to the Messenger of Allah, may Allah bless him and grant him peace.