Musnad Ahmad 658:152

'Abd al-Razzaq narrated to us, Sufyan informed us, from al-A'mash, from Abu al-Duha, from al-Bara' ibn 'Azib, who said: Ibrahim, the son of the Prophet, may God bless him and grant him peace, died at sixteen months old. He said: "Bury him in al-Baqi', for he has a wet nurse who will complete his nursing in Paradise."