Musnad Abu Ya'la al-Mawsili 121:5

Zuhayr narrated to us, Anas bin 'Iyad narrated to us, he said: I heard Rabi'ah al-Ra'y saying: Anas bin Malik said: The Messenger of Allah (may Allah bless him and grant him peace) passed away while he was sixty years old, and there were not twenty white hairs on his head and his beard.