Musnad Ahmad 20:15

'Affan narrated to us, Hammad bin Salamah narrated to us, from Ibn Abi Rafi', the freed slave of the Messenger of Allah (may Allah bless him and grant him peace), that 'Abdullah bin Ja'far used to wear his ring on his right hand. And he claimed that "the Prophet (may Allah bless him and grant him peace) used to wear his ring on his right hand."