Musnad Abu Ya'la al-Mawsili 115:278

Ibrahim ibn Sa'id al-Jawhari narrated to us, Muhammad ibn 'Isa al-Taba' narrated to us, from 'Abbad ibn al-'Awwam, from Sa'id, from Qatadah, from Anas: That the Messenger of Allah, may Allah bless him and grant him peace, used to wear his ring on his right hand.